Syria conference leaves open Assad question GENEVA - An international conference on Saturday accepted a U.N.-brokered peace plan for Syria, but left open the key question of whether the country's president could be part of a transitional government. The U.S. backed away from insisting that the plan explicitly exclude President Bashar Assad from any role in a new government, hoping the concession would encourage Russia to put greater pressure on its longtime ally to end the violent crackdown that the opposition says has claimed over 14,000 lives. U.S. Secretary of State Hillary Clinton insisted that Assad would still have to go, saying it is now "incumbent on Russia and China to show Assad the writing on the wall." "There is a credible alternative to the Assad regime," she said. What we have done here is to strip away the fiction that he and those with blood on their hands can stay in power. Moscow had refused to back a provision that would call for Assad to step aside, insisting that outsiders cannot order a political solution for Syria and accusing the West of ignoring the darker side of the Syrian opposition. The opposition has made clear it would not take part in a government in which Assad still held power. Russian Foreign Minister Sergey Lavrov underlined that the plan does not require Assad's ouster, saying there is "no attempt in the document to impose on the Syrian people any type of transitional process." More than a year into the uprising, Syria's opposition is still struggling to overcome infighting and inexperience, preventing the movement from gaining the traction it needs to instill confidence in its ability to govern. The U.N. plan calls for establishing a transitional government of national unity, with full executive powers, that could include members of Assad's government and the opposition and other groups. Syria envoy Kofi Annan said following talks that "it is for the people of Syria to come to a political agreement." "I will doubt that the Syrians who have fought so hard to have independence ... will select people with blood on their hands to lead them," he said. The envoy had earlier warned the permanent members of the U.N. Security Council -- Britain, China, France, Russia and the United States -- that if they fail to act at the talks hosted by the United Nations at its European headquarters in Geneva, they face an international crisis of "grave severity" that could spark violence across the region and provide a new front for terrorism. "History is a somber judge and it will judge us all harshly, if we prove incapable of taking the right path today," he said. Syria, verging on a full-blown civil war, has endured a particularly bloody week, with up to 125 people reported killed nationwide on Thursday alone. The opposition's divisions are tied to issues at the heart of the revolution: Whether to seek dialogue with the regime and what ideology should guide a post-Assad Syria. Rami Abdul-Rahman, director of the Britain based Syrian observatory for human rights, said following the agreement that "no member of the Syrian opposition will accept to be part of a transitional government while Assad is still in power." "Assad's staying in power will mean the continuation of the bloodshed in Syria," he said. Unlike Libya's National Transitional Council, which brought together most factions fighting Qaddafi's regime and was quickly recognized by much of the international community, Syria's opposition has no leadership on the ground. Regime opponents in Syria are a diverse group, representing the country's ideological, sectarian and generational divide. They include dissidents who spent years in prison, tech-savvy activists in their 20s, former Marxists, Islamists and Paris-based intellectuals. Communication between those abroad and those in the country is extremely difficult. Political activists in Syria are routinely rounded up and imprisoned. Many have gone into hiding, communicating only through Skype using fake names, and the country is largely sealed off to exiled dissidents and foreign journalists. International tensions also heightened last week after Syria shot down a Turkish warplane, leading to Turkey setting up anti-aircraft guns on its border with its neighbor. British Foreign Secretary William Hague noted that U.N. Secretary-General Ban Ki-moon told diplomats a U.N. monitoring mission in Syria would have to be pulled back if no diplomatic solution is found. We haven't reached agreement in advance with Russia and China -- that remains very difficult. I don't know if it will be possible to do so. In the interest of saving thousands of lives of our international responsibilities, we will try to do so," Hague told reporters. It's been always been our view, of course, that a stable future for Syria, a real political process, means Assad leaving The head of the struggling U.N. observer mission, Norwegian Maj. Gen. Robert Mood, has described the 300 monitors approved by the U.N. Security Council to enforce a failed April cease-fire as being largely confined to bureaucratic tasks and calling Syrians by phone because of the dangers on the ground. Their mandate expires on July 20. If that comes through political dialogue, we are willing to do that," said Khalid Saleh, a spokesman for the Syrian National Council, a coalition of Syrian opposition groups based in Istanbul, Turkey. Clinton said Thursday in Riga, Latvia, that all participants in the Geneva meeting, including Russia, were on board with the transition plan. The United Nations says violence in the country has worsened since a cease-fire deal in April, and the bloodshed appears to be taking on dangerous sectarian overtones, with growing numbers of Syrians targeted on account of their religion.