Jarabulus (Syria) (AFP) - Pro-Turkish armed groups have reinforced their presence on the outskirts of the city of Manbij in northern Syria as Ankara threatens a new offensive against Kurdish forces, sources said Wednesday.
Turkey announced in mid-December that it would launch a fresh military campaign against the Kurdish People's Protection Units, a militia in Syria that Ankara considers a terrorist group.
The United States has backed Kurdish fighters in northern Syria as part of an international coalition against the Islamic State jihadist group.
But a surprise announcement by US President Donald Trump a week ago that he will pull American troops out of the country has left the Kurds exposed to attack.
Pro-Turkish factions and opposing fighters in the city of Manbij are "consolidating their positions and massing reinforcements on the demarcation line" separating the two sides, said Rami Abdel Rahman, head of the Syrian Observatory for Human Rights, a British-based war monitor.
"Military operations haven't started -- there are no clashes or skirmishes," he said.
Turkey has massed reinforcements at the border, and dispatched tanks and armoured vehicles near Manbij, which hosts American troops and where Ankara says Kurdish forces also remain present.
Dozens of pro-Turkish fighters equipped with assault rifles were seen near the city of Jarablus in mud-splattered pick-up trucks on Tuesday, travelling to join sectors near the demarcation line, an AFP correspondent said.
But the situation was calm, he added.
- 'Final preparations for battle' -
The pro-Turkish Al-Jaish al-Watani rebel coalition said Wednesday it was finalising preparations for the planned offensive.
"We are in final preparations for the battle of Manbij, then (the battle) east of the Euphrates" river, the group's spokesman Yussef Hammud said on Wednesday.
He told AFP that the offensive would be in line with the "US withdrawal from the region".
"We await the political agreements between the US and Turkey concerning the withdrawal", he said.
The YPG says it has already left Manbij, but Ankara maintains that there has been no pullout of Kurdish forces from the city.
Sherfane Darwish, a spokesman for the Manbij Military Council -- a faction affiliated to the Kurdish-Arab Syrian Democratic Forces - has said his forces are on a "state of alert" due to military movements by Turkey and its Syrian rebel allies.
"There is an increased mobilisation of reinforcements at the border, and we are monitoring that", he told AFP.
"Patrols by the (international) coalition are still taking place -- nothing has changed. We are ready to repulse any attack", he said.
More than 360,000 people have been killed since Syria's war erupted in 2011.
The brutal repression of anti-government protests was followed by various countries intervening militarily in support of and against President Bashar al-Assad's regime.