Turkey has called on the US and other members of the international coalition in Syria to join in a ground offensive and "stop this war".

Speaking amid speculation that Turkey was preparing troops to enter Syria from the north over the weekend, Ankara said it refused to take action on its own.

But an official briefing reporters in Istanbul said "we want a ground operation", adding that "if there is a consensus, Turkey will take part".

"Turkey is not going to have a unilateral ground operation. We are asking coalition partners that there should be a ground operation. We are discussing this with allies.

"Without a ground operation, it is impossible to stop this war," he added.

Saudi Arabia said on Monday that it too was "very serious" about sending ground troops into Syria to remove President Bashar al-Assad.

The Saudi foreign minister, Adel al-Jubeir, said the country was waiting to see if a ceasefire brokered by the US and Russia would prove successful.