Sending foreign troops into Syria will lead to a "a full-fledged, long war", Russian Prime Minister Dmitry Medvedev has warned in an interview.
He spoke out after John Kerry, the US Secretary of State, said that more foreign troops could enter the conflict if attempts to reach a diplomatic solution fail.
The US has ruled out sending in ground troops - but Saudi Arabia this month offered to send ground forces to fight Islamic State.
Mr Medvedev hit back at Mr Kerry today in an interview with Euronews TV station, saying he should have held back his “futile words".
Major powers agreed on Friday to pause combat operations which have left at least 125,000 dead in the war-torn country.