The Syrian president, Bashar al-Assad, has said Turkey will pay a heavy price for backing rebels fighting against him, and accused it of harbouring "terrorists" who, he claimed, would soon turn on their hosts.

In an interview with Turkey's Halk TV due to be broadcast on Friday, Assad called the Turkish prime minister, Recep Tayyip Erdogan, "bigoted" and said Ankara was allowing terrorists to cross into Syria to attack his army and civilians.

"It is not possible to put terrorism in your pocket and use it as a card. It is like a scorpion which won't hesitate to sting you at the first opportunity," Assad said, according to a transcript from Halk TV.

"In the near future, these terrorists will have an impact and Turkey will pay a heavy price for it."

Turkey shelters about a quarter of the two million people who have fled Syria and has allowed rebel fighters to cross in and out of Syria.

Last month, the al-Qaeda-affiliated Islamic State of Iraq and the Levant seized Azaz, about 5km from the border with Turkey, and has repeatedly clashed with the local rebel FSA brigades since then.

'Sectarian agenda'

Assad accused Erdogan, whose AK Party has its roots in conservative Islamist politics, of having a sectarian agenda.

"Before the crisis, Erdogan had never mentioned reforms or democracy, he was never interested in these issues. Erdogan only wanted the Muslim Brotherhood to return to Syria, that was his main and core aim," he said.

Assad again denied his forces had used chemical weapons and blamed such attacks on the rebels. Asked whether he expected the Geneva process to accelerate if Syria handed over its chemical weapons, Assad said he saw no link.

"Practically these issues are not related. Geneva II is about Syria's own domestic political process and cutting neighbouring countries' weapons and financial support to terrorists," he said.