Syrian rebel militias battled two small armed groups suspected of links to ISIS in Qunaitra province near the border with Israel, with at least 38 people killed in days of clashes, a spokesman and activists said.

The ISIS group is not known to have a significant presence in southern Syria, but Maj. Isam al-Rayyes, spokesman for the rebel Free Syrian Army’s Southern Front, said a group known as Jihad Units ambushed some of his fighters in Qunaitra who were on their way to join an offensive against regime troops.

He said the Southern Front has long suspected the Jihad Units of being loyal to ISIS. After the ambush, the militants raised black flags similar to those carried by ISIS.

Six of the Southern Front fighters were killed in the ambush, Rayyes said. Soon after, another ambush resulted in the kidnapping of two fighters, he said.

The Britain-based Syrian Observatory for Human Rights said 38 people, including at least nine from the Jihad Units and three Saudi nationals, have been killed in the fighting since Monday.

The rebels have vowed to clear the Jihad Units from the province, and Rayyes said his men are currently besieging about 200 Jihad Units fighters in a village south of Qunaitra.

The ISIS-affiliated group is also referred to by some as the Jihad Army.

Fighters from the Al-Qaeda-affiliated Nusra Front and Ahrar al-Sham, a hard-line Islamist rebel group, have also joined in the fight against the Jihad Units, Rayess said, although there is no coordination.

“We will not allow for the presence of ISIS in the southern front,” Rayyes said in a telephone interview. In an offensive last year, the rebels seized most of Qunaitra province, which is also considered a gateway to the capital. The confrontation also saw the Nusra Front, Ahrar al-Sham and Islamist militias clash with the Yarmouk Martyrs Brigade, which last year emerged as a small rebel militia that had pledged allegiance to ISIS.

The Observatory said the clashes, which were spread over five villages and towns, killed a prominent Nusra military commander from the same hometown as Abu Mohammad al-Golani, the leader of the Nusra Front.

The Yarmouk Martyrs Brigade sparked the confrontation by seizing a headquarters of the Nusra Front in the area, the Observatory said.

Rebel groups posted several items of video footage purporting to show the anti-ISIS forces using tanks in the battles.

Elsewhere, regime airstrikes killed at least 21 people, including six children, and wounded 50 on in the provinces of Aleppo and Idlib.

Explosives-filled barrels and missiles were used in the wave of bombing. In Idlib, airstrikes killed 10 people, five of them children, said the Britain-based monitor, which relies on a network of sources on the ground for its reports.

A newly formed rebel alliance calling itself the Army of Conquest has seized key positions in Idlib province in recent weeks, including the provincial capital of the same name, the town of Jisr al-Shughur and a military headquarters.

Meanwhile, Syria’s defense minister Gen. Fahd Freij discussed anti-terror efforts with his Iranian counterpart, Gen. Hossein Dehqan, during a visit to Tehran.

In New York, Iran’s foreign minister said Arab and Western demands for the ouster of President Bashar Assad have fueled years of unnecessary bloodshed by blocking talks on a political settlement.

Mohammad Javad Zarif said outsiders deciding that Assad should not be part of any political process was a mistake.

“You cannot tell [Syrians] that this person should not be a part of your future, the other person should not be a part of your future,” he said. “This will prevent a negotiation from taking place.”

25 fighters from the militant group of Islamic State were killed after a strong blast occurred in their explosive manufacturing plant in Syria on Wednesday.

Britain-based Syrian Observatory for Human Rights (SOHR) which provides information about the ongoing war in Syria is reporting that the IS explosives factory was destroyed in the explosion.

“A strong explosion took place this evening in an IS explosives factory in the town of Al-Mayadeen in the province of Deir Ezzor,”, SOHR report states.

The report adds that “Several other explosions followed, shaking the whole town. Twenty-five ISIS fighters were killed, around 20 others were injured.”

Most parts of Deir Ezzor province in Syria are in the hands of self proclaimed Islamic State.

In order to break the stalemate in the ongoing conflict in Yemen, Saudi Arabia has reportedly started training hundreds of Yemeni tribesmen to fight the Houthis on the ground, while Riyadh continues its bombardment campaign.

“You cannot win a war against the Houthis from the air – you need to send ground forces in, but now there’s a program to train tribal fighters on the border,” a Doha-based military source familiar with the matter told Reuters.

According to another Yemeni official source, some 300 fighters have already managed to return to Yemen after getting Saudi training. They were allegedly send the Sirwah district in the central Marib province to battle Houthis in the area. According to the source the newly trained unit managed to push the rebels back.

Saudi Arabia’s coalition spokesman failed to either confirm or deny the reports.

“We always confirm that we are helping the resistance and the popular groups, the loyal army … but we cannot go into details on where, how, how much,”Brigadier Ahmed Asseri said.

The training received by the Yemeni tribesmen in Saudi Arabia allegedly includes light weapons and tactical advice knowledge. According to another Reuters source, the Kingdom plans to boost deployment of such units to fight the Houthis resistance.

Rhiayad is reportedly gathering all tribal leaders loyal to the ousted president Abd-Rabbu Mansour Hadi, who fled to Saudi Arabia, to unite their tribal forces against those of the Houthis.

“Saudi Arabia wants to unite tribal leaders in this meeting but the feeling is that there’s not much hope for that,” a Yemeni source in Riyadh told Reuters. Apparently the tribal delegations seem more concerned battling the jihadi elements in Yemen in addition to the Houthi opposition.

“The Saudis have decided that they are going to intensify the unstable situation by providing arms to an oppositional group, a group that has been traditionally oppositional to the Houthis,” Ajamu Baraka, Middle East expert told RT.

On the ground in Yemen, the Shiite Houthi fighting force and army units loyal to former president Ali Abdullah Saleh are in control of central and southern areas.

The fighting is ongoing on a number of major fronts. In Aden, the Houthis are engaging tribesmen who are supported by Saudi-led air forces. In Yemen’s third largest city, Taiz, Houthis are fighting the Sunni Islamist fighters. The Houthis and their allies have been also fighting both Islamists and local tribesman in Marib and in Shabwa provinces.

The forces in Yemen which Saudi Arabia is arming can turn jihadi, Baraka says, as they have some “traditional, Whabis, Islamic leanings,” which is the “main ideological, Islamic foundation for Al Qaeda.”

“The only force that is gaining as a consequence of this conflict is in fact Al-Qaeda,” he went on to stress.

Meanwhile, the airstrikes continued throughout the country on Wednesday, targeting Houthi forces in Aden, Saada, Hajja, Taiz, Ibb and Bayda.

The fighting in Yemen continues despite all sides of the conflict being willing to hold peace talks.

“The Saudis have an objective which is connected to the interest of Israel which is basically to perpetuate the narrative that Houthis are the proxy force of Iran,” Baraka said, adding that such policy also suits Washington.

Since the Saudi-led bombings started on March 26, more than 1,000 people, including an estimated 551 civilians have been killed, the United Nations said last week. UNICEF said at least 115 children were among the dead.

Prominent Iraqi Shi’ite cleric Muqtada al-Sadr has called on the Shi’ite world to unite and wage jihad against invaders and extremist groups.

Sadr claimed in a statement that neighbouring Arab countries are planning an “intervention” in Iraq.

Several Arab states have joined the U.S.-led coalition to combat Islamic State (IS) militants in northern Syria and Iraq, while Saudi Arabia recently deployed its military against Shi’ite Houthi rebels in Yemen.

Sadr has now claimed that the al-Hashid al-Shaabi Shi’ite militia – an anti-IS force – now faces political challenges within its membership, causing a lack of unity.

The leading cleric – who formed the Mahdi Army militia group in April 2003 – also called for the expulsion of al-Hashid al-Shaabi members “who want to politicize jihad and victories against IS to use them for their gains.”

Al-Hashid al-Shaabi was established after a fatwa, a religious ruling, was issued by by Iranian-born Shi’ite leader Ayatollah Ali al-Sistani in June 2014. Its purported role was to fight against IS insurgents in support of Iraqi Shi’ite forces.

Sadr also said: “There are plans for an Arabic intervention in the region and that should be prevented by rushing to liberate Anbar Province and Mosul.

“Hence, we stand against any foreign intervention and I call upon the government not to depend on the Americans to end terrorism in Iraq.”

Iranian forces fired warning shots across the bridge of a Marshall Islands-flagged cargo vessel as it was traversing the Strait of Hormuz, boarded the ship and directed it toward the Iranian mainland, a Pentagon official said Tuesday.

The incident, which prompted the U.S. Navy to dispatch a destroyer and a plane in response, comes as Iran and the U.S., along with other world powers, try to hammer out a final deal over Tehran’s nuclear program.

The ship was traveling through the narrow strait, which is technically Iranian territorial water, but under international agreement is open to foreign ships making an innocent passage, said Col. Steve Warren, a Pentagon spokesman. It wasn’t clear whether the ship had strayed off course into coastal waters not protected by that agreement.

The master of the cargo ship MV Maersk Tigris had initially refused an Iranian order to move further into Iranian waters, but after the warning shots were fired the vessel complied, Warren said.

The cargo ship was directed to waters near Larak Island, he said. The island sits off the major Iranian port of Bandar Abbas and is one of several in the Strait of Hormuz.

Iranian state television reported that only 24 crew were onboard the vessel, and hailed from Britain, Bulgaria, Romania and Myanmar. It said the ship was seized based on a court order due to unspecified violations. Iranian officials could not immediately be reached for comment.

Bandar Abbas is the main port for Iran’s navy and separate naval forces operated by the elite Revolutionary Guard, as well as the country’s primary commercial port. It overlooks the Strait of Hormuz, the highly strategic waterway at the mouth of the Arabian Gulf.

The strait is the route for about a fifth of the world’s oil and is only about 33 kilometers wide at its narrowest point. Ships traversing the chokepoint have even less room to maneuver. The shipping lane in either direction is only 3 kilometers wide, with a 3-kilometer buffer zone between them.

Iran has in the past threatened to block the strait, a move that could spark a military conflict in the Gulf. American and allied naval forces routinely patrol the strait and have conducted military drills aimed at countering threats such as sea mines that Iran might use to close the waterway.

Tehran frequently conducts military exercises of its own in and around the strait. Large-scale, live-fire naval drills in February saw Revolutionary Guard forces assault a replica of a U.S. aircraft carrier built in a Bandar Abbas shipyard.

“It is inappropriate” for the Iranians to have fired warning shots across the ship’s bridge in Tuesday’s circumstances, Warren said. He said it was too early to know whether the Iranian intervention amounted to a violation of the freedom of navigation through a waterway heavily used by international shipping.

Warren said the cargo ship had been boarded by Iranians, but no one was injured and no Americans were involved. The spokesman said the U.S. government has “certain obligations” to defend the interests of the Marshall Islands, but he was uncertain how those obligations to the Pacific Ocean nation apply in this situation.

The Iranian vessels, numbering five or six, were with the Iranian Revolutionary Guard Corps Navy, he said. The incident began at about 4:05 a.m. U.S. Eastern Daylight Time, he said.

After the cargo ship sent a distress call, the U.S. Navy sent the destroyer USS Farragut and a Navy maritime patrol and reconnaissance aircraft to the area of the incident to monitor the situation, according to Warren.

In 2007, Revolutionary Guard forces captured 15 British sailors and marines from a frigate in the Gulf, accusing them of operating in Iranian waters. They were released less than two weeks later.