UK Foreign Secretary William Hague on Monday said discussions on sending a joint United Nations-Arab League peacekeeping mission to Syria must take place "urgently," the Press Association (PA) reported.But no such mission can take place, Hague added, until Syrian President Bashar Assad ends the violence being perpetrated by his military, PA reported. "President Assad must be in no doubt of the determination of his neighbors and the international community to bring an end to the violence in Syria," he said. Saying the UK would play a "very active part" in a new international working group on Syria, the UK foreign secretary praised recent actions by the Arab League. "The Arab League could not have sent a clearer message to Syria than the one it sent yesterday," adding that he plans to work closely with the League in the near future.Russia is studying the Arab-UN proposal to send a peacekeeping mission to Syria but wants more details and says violence should end before any such mission takes place, Foreign Minister Sergei Lavrov said on Monday.Lavrov repeated at a news conference Russia's message that international pressure to end nearly a year of bloodshed in Syria should focus on the Syrian opposition as well as the government. Earlier Monday, China's Foreign Ministry backed Arab League mediation in Syria but offered no clear sign of support for its call to send in peacekeepers to halt the Syrian government's violent crackdown on opposition groups.Chinese Foreign Ministry spokesman Liu Weimin would not be drawn on whether Beijing supports sending in peacekeepers.In a meeting in Cairo on Sunday, Arab League ministers called for a joint UN-Arab peacekeeping force in Syria.The Arab League urged the Syrian opposition to unify its ranks and for “providing all forms of political and material support to it.”As part of the Arab efforts, Tunisia said it would host the first meeting on February 24 of a “Friends of Syria” contact group made up of Arab and other states, and backed by Western powers.The resolution said Arabs would scrap their monitoring mission, which had been sent to Syria in late December, but was criticized by Syria’s opposition as ineffective from the outset. It also faced internal dissent and logistical problems.On Sunday, the Sudanese general leading the observers quit.In place of the Arab team, the League called for the UN Security Council to issue a resolution setting up a joint UN-Arab peacekeeping mission to go to Syria.League chief Nabil Elaraby has already proposed such a joint mission to the UN secretary-general, but the plan has drawn lukewarm support from diplomats at the United Nations in New York. The United States and Germany said they were studying it.