ANKARA/BEIRUT: Turkey sent 80 military vehicles including tanks to its southwestern border with Syria, the state-run Anadolu news agency said Sunday. Citing a military source, Anadolu said the deployment was part of reinforcements for troops stationed along the border. The vehicles were sent to the Iskenderun district of the southeastern province of Hatay, Anadolu said.

Late Saturday, Anadolu also reported that the army had dispatched first aid trucks and military vehicles to the same location, along with heavy equipment.

A third convoy of armored vehicles was heading to Hatay’s Reyhanli district, where Turkey’s Cilvegozu border gate with Syria is located, Anadolu said.

Turkey’s Foreign Ministry said Friday that Russia, Iran and Turkey had agreed to deploy observers around a “de-escalation zone” in northern Syria’s Idlib region, which is mostly controlled by militants linked to a former Al-Qaeda affiliate.

It said the observers would look to prevent clashes between forces of the Syrian army and the opposition, and watch for cease-fire violations.

Last month, Turkish Prime Minister Binali Yildirim said Turkey was taking necessary measures along its 150-kilometer border with Idlib.

In other developments Sunday, Syrian troops seized the Jafra district in the eastern city of Deir al-Zor Sunday, tightening the noose around Daesh (ISIS), a Syrian military source said. The district is located on the western bank of the Euphrates River. The army pushed into the city this month with the help of Russian air power and Iran-backed fighters, breaking a Daesh siege of an enclave there that had lasted three years.

“They have no outlet except crossing the Euphrates toward the eastern bank and fleeing toward the desert, or [the towns] Albukamal and Mayadin,” the source told Reuters.

Moscow and Washington are backing separate offensives in the oil-rich province of Deir al-Zor bordering Iraq.

Both have advanced from opposite sides of the Euphrates, which bisects the province, Daesh’s last major foothold in Syria.

Russian- and U.S.-backed offensives against Daesh have mostly stayed out of each other’s way, with the Euphrates often acting as the dividing line.

But the Pentagon accused Russia this week of bombing U.S.-backed forces on the river’s eastern bank.

Russia’s Defense Ministry rejected the allegations Sunday. Moscow had warned the United States well in advance of its operational plans and its jets only targeted Daesh militants, it said.

Russia’s RIA news agency cited an unidentified source as saying the Syrian army had cut Daesh’s main supply line in Deir al-Zor city.

The government now controls two-thirds of Deir al-Zor, according to the Britain-based Syrian Observatory for Human Rights activist group.

Russian jets pounded movements across the river as Daesh fighters tried to escape in ferries, and many civilians, including families of the militants, had also tried to flee across the river in recent days, it said.

Separate airstrikes by Russia and by the U.S.-led coalition killed more than 34 people, including children, across Deir al-Zor province over the past day, the Observatory said.

Daesh controls much of the desert region around Deir al-Zor city, where its fighters are also under attack from the U.S.-backed Syrian Democratic Forces alliance. With jets and special forces from the U.S.-led coalition, the alliance of Kurdish and Arab militias is battling Daesh in the northern parts of Deir al-Zor province.

The SDF said it had taken 14 villages and farms, two towns and some factories on the eastern bank of the Euphrates since launching its assault last week.

The march by the SDF aims to prevent Syrian troops and their allies from expanding their presence along the border with Iraq.

Also Sunday, the U.N.’s World Food Program halted its airdrops to Deir al-Zor after its trucks were to reach the city with food relief, for the first time since May 2014.

A five-truck convoy brought with it enough wheat to feed 70,000 people, the organization said in a statement.

After breaking the siege, Damascus immediately began organizing its own aid deliveries to the city, replenishing empty store shelves with basic goods. Prices for basic foodstuffs have fallen by 25-30 percent since the final days of the siege, according to Gaziantep-based Ali Rahbe, of the activist-run Justice For Life monitoring group.