Reyhanli, Turkey - Turkish forces downed a fighter jet flown by Syrian government forces over southern Idlib on Tuesday as a strategic town in northwest Syria fell under the control of President Bashar al-Assad's military.

It was the third such shoot-down in three days after Turkey hit two other Syrian aircraft on Sunday.

"Turkish regime forces targeted one of our warplanes, which led to its fall in the northwest area of Maarat al-Numan," Syrian state media reported.

On Twitter, the Turkish defence ministry confirmed the news, saying "an L-39 plane belonging to the [Syrian] regime has been downed".

Meanwhile, Syrian government forces overnight took over the key city of Saraqeb, which lies at the junction of the M4 and M5 commercial highways that connect the country's major cities.

Saraqeb has changed hands twice in the last month, but a dramatic escalation in fighting over the past few days saw armed opposition groups retreat to the villages of Nairab and Afis in the west, as Syrian government forces - under cover of Russian air power - secured the city.

Rashwan Abu Hamza, a field commander in Saraqeb belonging to one of the rebel groups, told Al Jazeera the battle against al-Assad's forces intensified on Monday night.

"Regime forces began to advance into the city at 2am and an hour later entered the neighbourhoods and began combing them," Abu Hamza said. "The shelling from Russian warplanes escalated and forced us to withdraw west of the city."

At 4am (01:00 GMT) on Tuesday, Saraqeb was under the full control of the Syrian forces, he said, but added a counteroffensive was imminent.

'Operation Spring Shield'

Since December, al-Assad's forces intensified their offensive to take control of Idlib province, the last rebel stronghold in Syria where Turkey backs some opposition fighters.

The operation has resulted in the internal displacement of nearly one million Syrians, the majority fleeing to the Turkish border, and killed at least 300 civilians.

Under the 2018 Sochi agreement with Russia, which designated Idlib as a de-escalation zone, Turkey set up several observation points throughout the province, but incurred heavy losses as Syrian forces targeted its troops.

Turkey launched a military operation it called Spring Shield, its fourth and biggest intervention yet into Syria's nine-year civil war. It came in response to the killing of 34 Turkish soldiers in Idlib last week, the deadliest strike against the Turkish army in decades.

Turkey's defence ministry said so far more than 2,500 Syrian soldiers have been "neutralised" - a term that means wounded, captured or killed.

The head of Turkey's far-right Nationalist Movement Party (MHP), Devlet Bahceli, said in Ankara on Tuesday the threat from across the border demanded military action.

"Turkey is not joking. The Idlib issue is directly related to the survival and protection of a homeland. Russia and Syria should not try Turkey's patience anymore," said Bahceli.

Return to Idlib

At the Reyhanli-Cilvegozu border crossing on the Turkish side, Ahmad Abeed stood near the gate smoking a cigarette.

The 22-year-old, who works in a hazelnut factory in Antakya, has been in Turkey for the past five years, but is now longing to return to Syria where his parents and siblings are.

"My family are from a village in Saraqeb's countryside," he said. "Two weeks ago they were displaced to Sarmada."

Abeed wants to enter Idlib to fight against the Syrian government forces.

"When I first came to Turkey, I thought the war in Syria would end after a year or two," he said. "I didn't support any side. But now the enemy is clear. I can't leave my younger sisters inside to die, so that's why I want to pick up arms."

A few metres next to him, Umm Asad stood facing the border crossing, her eyes full of tears.

"I've been trying to go back to Idlib for a while now," she told Al Jazeera, holding her one-year-old daughter Shams.

"I want to be with my children who are frightened out of their wits by the shelling. They need their mother," Umm Asad said.

Her husband and two other children are in the town of Binnish, some 6km (3.7 miles) from Saraqeb. Heavily pregnant at the time, Umm Asad left her family a year ago to accompany her six-year-old son to a hospital in Turkey's Hatay for a medical emergency.

Her son is now in a permanent comatose state, and she longs to return to Idlib.

"I don't have a house in Hatay," she said. "I gave birth to Shams here and rely on the kindness of my relatives here. But my children need me," she said.