A top US envoy expressed doubts on Wednesday about the prospects for a ceasefire in Syria, accusing President Bashar al-Assad of failing to keep past promises. “Many are duly sceptical about prospects for even a temporary ceasefire, given Assad’s record of broken promises,” US ambassador to the United Nations Susan Rice said after a briefing by UN-Arab League envoy Lakhdar Brahimi on his efforts to halt hostilities. Brahimi told the 15-nation Security Council on Wednesday that Assad and most rebel groups had agreed to his appeal for a four-day ceasefire during the Muslim holiday of Eid al-Adha. The Syrian government is to make an official statement on Thursday. “Regime atrocities – aerial bombardments, cluster bombs, shelling - are mounting in Syria and threatening the security of the entire region,” Rice said in a Twitter statement. She said the United States “strongly supports” Brahimi’s call for a ceasefire, but she added that the “government must make the first move.” Earlier, US Secretary of State Hillary Clinton said the United States wanted to see the violence end. But she added that there must be “consequences” for those who block any ceasefire or political transition in Syria. Clinton said in Washington that the United States and other major powers had “worked very hard” to agree a document on a document for a transition in Geneva in June. “We would like to see the Security Council adopt such a framework but to include some consequences for all parties in the event that there is not a cease-fire respected for a political transition” to start.