Syrian government forces pushed into an opposition stronghold on Thursday, as rebels forces allied with Turkey joined Ankara’s offensive against Kurdish militants in nearby Afrin.

Syrian troops and allied militia forces moved within 14 kilometres (9 miles) of the town of Saraqeb, in Idlib, the opposition's largest stronghold in the country, a war monitoring group reported.

The Syrian Observatory for Human Rights said pro-government forces were inching closer to a key highway connecting two of Syria's largest cities, Damascus and Aleppo, which passes just east of Saraqeb.

Syria's military leveraged its monopoly on air power to carve a path deep inside Idlib to reach the Abu Dhuhour air base, 26 kilometres (16 miles) southeast of Saraqeb, last month. It then started marching toward Saraqeb, an important military centre for rebels and al Qaeda-linked insurgents in control of Idlib.

"The bombing has been non-stop," said local media activist Abdulghani Dabaan.

The regime’s advance has been aided by Turkey’s move to mobilise some 10,000 Syrian opposition fighters to join its campaign against a Kurdish militant group approximately 50 kilometres (31 miles) to the north.

That campaign, codenamed Operation Olive Branch, has drawn protest from the US and France, who have relied heavily on the Kurds in the war against the Islamic State (IS) group.

French ‘insult’

Turkey considers the Kurdish People's Protection Units - or YPG - to be an extension of a Kurdish insurgency inside Turkey and views the group at its borders as a national security threat.

Ankara took umbrage at remarks by French President Emmanuel Macron, who warned against an "invasion operation".

Turkish Foreign Minister Mevlut Cavusoglu called the warning an "insult" and said Thursday that France was in no position to "teach a lesson" to Turkey over its cross-border offensive, referring to past French military interventions in Algeria and other parts of Africa.

Cavusoglu said France understood that Turkey was fighting "terrorists" and did not aim to invade Afrin.

Some 15,000 civilians have been driven by the joint Turkish-Syrian opposition campaign into the Kurdish-controlled city of Afrin, according to UN humanitarian adviser Jan Egeland.

Egeland spoke Thursday to reporters in Geneva after a regular meeting of world and regional powers in a UN humanitarian "task force" for Syria.

He said booby traps and mines planted by the IS group in Raqqa have killed or wounded an average 50 people per week since US-backed fighters - notably the YPG - expelled the jihadist group from the city in October.

Opposition wants UN to lead constitutional reform

Also on Thursday, the Syrian opposition's Higher Negotiations Committee (HNC) said it was ready to back a Russian-brokered constitutional reform initiative for Syria, so long as it's led by the United Nations.

Any constitutional committee must be formed at the UN, and include representation from the HNC, which represents the Syrian opposition in UN talks with the government in Geneva, said HNC chief Nasr al-Hariri.

He spoke in Istanbul at a press conference on Thursday, two days after Russia convened a peace conference for Syria that was boycotted by the HNC as well as the Kurds and Western powers.

Deciding the committee's makeup could doom the initiative before it even takes wing. Syrian state media, a government mouthpiece, says Damascus will have two-thirds of the representation on the committee.

Hariri said the HNC would not accept having a committee appointed in Sochi, the Black Sea resort where the Russian-brokered talks have taken place.

(FRANCE 24 with AP)

Date created : 2018-02-01