Ankara responded swiftly after Monday's major provocation, firing dozens of rockets at pro-government positions south of Saraqeb, according to a source who spoke The New Arab's Arabic-language sister site.Heavy shelling also targeted the government strongholds of neighbouring Hama and Latakia.Turkish Defence Minister Hulusi Akar claimed 54 targets were hit and 76 Syrian government soldiers "neutralised", as cited by Anadolu news agency.In an Istanbul press conference earlier, Turkish President Recep Tayyip Erdogan alluded to the large losses Syrian President Bashar al-Assad's forces were likely to incur during the reprisal."The operation is ongoing...according to initial reports, between 30 and 35 soldiers from the Syrian side have been neutralised," Erdogan said.In the same press conference, he delivered a firm warning to key Syrian ally Russia to steer clear of his country's path as it responded to the regime's act of aggression."You are not the side we are now dealing with. We hope you do not hinder on our activities," he added."Those who test Turkey's determination with such vile attacks will understand their mistake," the Turkish leader said.He added that Turkish officers were in close communication with their Russian counterparts and conducting their operations accordingly.According to sources from within the Turkish government who spoke to The New Arab, Turkey sent reinforcements into Idlib to build defence instalments along the strategic M4 and M5 highways which link Damascus, Aleppo and Idlib.Turkey's defence ministry said its forces were attacked despite prior notification of their coordinates to the local authorities.The Russian defence minister however claimed that Turkey had failed to notify the Russian military and the troops were hit by Syrian fire directed at "terrorists" - a reference to al-Qaeda-linked militants - west of Saraqeb.The exchange of shelling between Syria and Turkey is among the deadliest since Turkey deployed troops in Syria in 2016.A 2018 demilitarisation agreement to create a 'buffer zone' in Idlib offered provisions for the Turkey to maintain 12 observation posts in rebel-held areas.

Heightened attacks by the regime and Moscow in the region have displaced more than 388,000 people since December, according to the United Nations, forcing many towards the Turkish border.

Ankara, host to more than three million Syrian refugees, fears the latest fighting will lead to another mass influx.

UN Secretary-General Antonio Guterres on Saturday called for an end to fighting but air strikes, many of them carried out by Russian aircraft, have continued.

On Monday, at least nine civilians were killed in an air strike on northwest Syria where similar raids conducted a day earlier killed 14 civilians, according to the SOHR.

The regime know controls more than two thirds of Syria, but Hayat Tahrir al-Sham, a jihadist group led by members of Syria's former Al-Qaida affiliate, still control swathes of territory in and around Idlib province, where pro-Ankara rebel groups are also present.

In recent months, pro-Damascus forces have pressed northwards.

Government forces last week retook the key town of Maaret al-Numan along the highway and are now just a few kilometres from the abandoned town of Saraqeb.

Agencies contributed to this report.

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