The UK along with seven other nations have expelled their Syrian Ambassadors in protest at the murder of at least 108 civilians in the town of Houla.
The Foreign Secretary William Hague said that "the international community is appalled by the violence ... by the behaviour of the [Syrian] regime and by the murder of so many innocent people".
Australia, France, Germany, Italy and Canada have all made similar announcements today. Mr Hague said that the United States and Spain would be taking similar action.
The mass diplomatic expulsion comes just after the UN Envoy to Syria Kofi Annan warned President Assad that "bold steps" were needed to implement his six-point peace plan.
A statement from Mr Annan's aide read:
Kofi Annan met President Bashar al-Assad this morning to convey the grave concern of the international community about the violence in Syria, including in particular the recent events in Houla. He conveyed in frank terms his view to President Assad that the six-point plan cannot succeed without bold steps to stop the violence and release detainees, and stressed the importance of full implementation of the plan.
The Syrian government has denied it is responsible for the killing of at least 108 civilians in the town of Houla close to the restive city of Homs.
Today, UN investigators confirmed that the victims included 49 children and 34 women.
A spokesman for the UN stated categorically that it was "clear" that the Syrian army was responsible for shelling civilian areas over a period of 12 hours.
UN rights spokesman Rupert Colville said "it appears" that the pro-government Shabbiya militia was responsible for house-to-house summary executions, which accounted for the majority of the deaths in Houla.
– UN rights spokesman Rupert Colville
A few, a fairly small number appear to have been killed by shelling, artillery and tank fire, which took place over a period of more than 12 hours. But the majority appear to have been the result of house to house summary executions of armed men going into houses and killing men, women and children inside.
Earlier, the Australian Foreign Minister Bob Carr said that the decision to expel two Syrian diplomats was currently the only way to send a "message of revulsion" to the Syrian government.