Two Syrian fighter jets were downed by Turkish fighter jets on Sunday in Syria‘s northwestern Idlib province, as Turkey began a wide-scale military operation against the Assad regime in response to last week’s killing of 34 Turkish soldiers, according to Syria’s SANA state news agency.

The two Syrian pilots managed to deploy their parachutes and land safely, according to the Syrian military. SANA reported earlier on Sunday that the Syrian army had downed a Turkish drone over the town of Saraqeb in the Idlib region of northwest Syria.

Turkish Defense Minister Şule Akar announced the operation, named Operation Spring Shield, vowing retaliation against any attack on Turkish forces or observation posts in Idlib under Turkey’s right to self-defense.

“Some 2,200 Syrian regime troops, a drone, eight helicopters, 103 tanks, tens of howitzers, and three air defense systems were neutralized,” Akar said of the newly announced operation.

“We do not aim to face off with Russia. Our only aim is to stop the Syrian regime’s massacres, radicalization and migration,” he added.

Akar continued his plea for Russian assistance, saying that “Turkey expects Russia to use its influence to bring an end to the Syrian regime’s attacks, and its withdrawal to the Sochi-deal borders.”

Earlier, Syria’s army declared the airspace over northwest Syria closed to planes and drones, pledging to down any aircraft that violates it, state media said on Sunday, shortly before reports of the downed drone began surfacing.

“Any aircraft that violates our airspace will be dealt with as an enemy aircraft that must be brought down,” state news agency SANA said, citing a military source. Turkish forces have been hitting Syrian government targets in Idlib in recent weeks. In February, 55 Turkish soldiers were killed in Syrian government attacks, including air strikes, in Idlib.

The air strikes are part of a major assault to capture the province, part of the last remaining territory held by rebels backed by Turkey.

Turkish President Tayyip Erdogan said on Saturday that he had asked President Vladimir Putin for Russia to stand aside in Syria and let Turkey fight Syrian government forces alone, after last week’s killing of its soldiers.

“We went there because we were invited by the people of Syria,” Erdogan said. “We don’t intend to leave before the people of Syria say, ‘Okay, this is done.'”