Mr Hague made the strongly worded comments at a joint news conference yesterday in Moscow with Russian foreign minister Sergei Lavrov, whose government is an ally of the Assad regime.
Mr Lavrov said Russia wanted to see an end to violence by all sides in Syria and a political process based on respect for Syria’s “sovereignty, territorial integrity and independence”.
However, Mr Lavrov insisted rebels in Syria were partly responsible for the massacre of 108 people in Houla.
He said “both sides have obviously had a hand in the deaths of innocent people.”
Mr Hague dismissed claims that the bloodshed was caused by anti-government forces But in a sign of a split between the UK and Russia, he repeated his demand for President Assad to hand over power.
Mr Lavrov rejected the call saying: “For us it’s not the most important thing who is in power in Syria.”
Mr Hague said: “It is not as if the alternatives in Syria are the Annan plan or the Assad regime retaking control of the country.
“The alternatives are the Annan plan or ever-increasing chaos in Syria and a descent closer and closer to all-out civil war and collapse.”