The US has rubbished Turkish President Recep Tayyip Erdogan's claim that he had "complete evidence" to show that Washington offered support to Islamic State (Isis) in Syria.

Erdogan on Tuesday (27 December) said the US-led coalition forces also supported other groups like the Kurdish militants PYD (Democratic Union Party) and its armed wing, the People's Defence Units (YPG), which Turkey considers as terror organisations.

He said while the US has accused Ankara in the past of supporting the jihadists, Washington is assisting terrorists themselves.

"They were accusing us of supporting Daesh [Isis/IS]," Erdogan said during a press conference in Ankara. "Now they give support to terrorist groups including Daesh, YPG, PYD. It's very clear. We have confirmed evidence, with pictures, photos and videos," he said.

US State Department spokesman Mark Toner called the allegations "ludicrous" and said there was "no basis" for such claims. He said Washington was "100 percent behind the defeat, destruction of Daesh [Isis], even beyond Syria and Iraq".

He claimed terror networks were getting dismantled and destroyed around the region and in other parts of the world.

Toner added that the US was "working constructively with Turkey" to lead its coalition efforts in Syria. "Turkey is playing a part and we have constant dialogue and discussion with Turkey about how we can better leverage both of our efforts," he said during his daily press briefing.

The US-led forces have been supporting the moderate rebels in Syria who are fighting to oust their country's President Bashar al-Assad. The coalition has also been working with Kurdish groups in Syria, but Ankara claims they are linked to the Kurdistan Workers Party (PKK), a group which has been pursuing a decades-long uprising in Turkey.

In a multi-sided war in Syria, all the warring parties, including Turkish forces, are also fighting to push IS militants out of northern Syria.

At least 37 Turkish forces are reported to have been killed during an offensive that was launched in August to drive out IS militants and Kurdish fighters out of the area around al-Bab, near the Turkish-Syria border, the BBC reported.

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Turkish President Recep Tayyip Erdogan accused the US-led coalition of supporting not only Islamic State militants but also Kurdish militants PYD (Democratic Union Party) and its armed wing, the People’s Defence Units (YPG)Handout via Reuters