Washington: A senior US general has accused Russia of playing a destabilising role in Syria and acting as "both arsonist and firefighter," as a brief truce unilaterally declared by Moscow in the eastern Ghouta region collapsed.

The US and Russia have been on different sides of the multi-sided seven-year-war, with Russia being the key ally of Syrian President Bashar al-Assad whose forces are besieging eastern Ghouta, a rebel-held area near Damascus.

Smoke rising from Ghouta after a Syrian government airstrike. Credit:AP

"Diplomatically and militarily, Moscow plays both arsonist and firefighter, fuelling tensions among all parties in Syria ... then serving as an arbitrator, to resolve disputes, attempting to undermine and weaken each party's bargaining positions," said US Army General Joseph Votel.

Votel is the head of the US military's Central Command. He was speaking to a House of Representatives Armed Services Committee hearing.