Updated

France and Britain say they will push for tougher U.N. action against Syria if a transition plan doesn't bring a quick end to the violence.

Frustration in some quarters is growing with a U.N.-brokered peace plan that could allow President Bashar Assad to take part in a transitional government.

British Foreign Secretary William Hague said in Paris on Wednesday that if the plan "does not quickly bring results on the ground, then our countries are ready to return to the United Nations Security Council and to seek further measures."

French Foreign Minister Laurent Fabius says if the roadmap isn't applied fast "then we would come back to the United Nations" for tougher measures, including possibly those that could allow military intervention.

France is hosting an international conference on Syria's future Friday.