Ankara (AFP) - Turkey announced Friday it had deployed scores of soldiers in Syria's jihadist-controlled Idlib province in a bid to stop the fighting there.
The deployment also appeared to be aimed at preventing the expansion of Syrian Kurdish militia backed by the United States, but considered by Ankara to be "terrorists".
Over 100 soldiers, including special forces, and 30 armoured vehicles entered the northwestern Syrian region, Turkey's Hurriyet daily reported on Friday.
More troops could be sent there in the next few days, the paper added.
In a statement on Friday, the military said it had begun "activities to establish observation posts on October 12".
President Recep Tayyip Erdogan said Turkish troops had entered Syria with the Free Syrian Army, the name Ankara uses for rebels seeking Syrian President Bashar al-Assad's ouster.
"We said we would come unexpectedly in the night, and last night... we started the operation," he said during a televised speech in Ankara.
"It is us who has a 911-kilometre (556 miles)-long border with Syria, we are the ones threatened," he thundered.
Idlib is largely controlled by Hayat Tahrir al-Sham (HTS), a group led by Al-Qaeda's former Syria affiliate, which has ousted more moderate rebels in recent months.
The deployment comes days after Turkish troops launched a reconnaissance mission as part of efforts with Russia and Iran to set up a de-escalation zone -- as agreed in May at the Astana peace talks aimed at ending the Syrian war.
Turkey says it is backing Syrian rebels in a bid to oust HTS members in the area and allow Iranian, Russian and Turkish forces to implement the zone.
They agreed on four such ceasefire zones in Syria as a prelude to negotiations.
- Fortifying positions -
Three zones are already in place -- in Eastern Ghouta near Damascus, in central Homs, and in parts of southern Syria -- which are being monitored by Russian military police.
The fourth de-escalation zone includes Idlib but also parts of the neighbouring Latakia, Hama and Aleppo regions.
The operation's official target is the HTS but Britain-based Syrian Observatory for Human Rights head Rami Abdel Rahman told AFP the Turkish forces were escorted by HTS elements, suggesting a degree of coordination between them.
"The Turkish military appears to have been talking with Tahrir al-Sham, trying to avoid clashes and find an arrangement that both can live with," Aron Lund, a fellow with The Century Foundation, told AFP.
While Turkey supports Syrian opposition fighters and calls for Assad's ouster, Ankara has worked closely in the last few months with Russia -- which supports Assad -- in the hope of bringing the war to an end.
Idlib is one of the last major areas of Syria beyond the control of the government, which has recaptured vast swathes of territory from opposition fighters since its ally Russia intervened on its behalf in September 2015.
The Syrian conflict began after widespread protests against the government in 2011 but has since turned into a multi-front war that has killed more than 330,000 people.
- 'Ignite another war' -
The last time Turkish forces were engaged in Syria was in August, when Turkey launched its eight-month Euphrates Shield operation against jihadists and Kurdish militia in northern Syria.
One of Turkey's main concerns is the expansion of the Syrian Kurdish People's Protection Units (YPG), which Ankara says is linked to the Kurdistan Workers' Party (PKK) that is waging an insurgency inside Turkey.
Erdogan has repeatedly vowed he will not allow the YPG to form a "terror corridor" reaching the Mediterranean on Turkey's southern border.
Moustafa Sejari, a senior official in rebel group Liwa al-Moutassem taking part in the operation, said on Twitter the Turkish deployment was intended to "protect the region from bombing and to cut the path of (Kurdish) separatists".
The YPG accused Turkey of making threatening moves towards Afrin, the neighbouring region held by the militia.
"Turkey is not after anything in Idlib but (an) Afrin siege could ignite (the) fire of another war in the region," the YPG said on Twitter.