SAINT PETERSBURG (Reuters) - U.S. Secretary of State Hillary Clinton sought to raise pressure on Russia on Thursday ahead of a crucial meeting on the Syria crisis, saying all countries involved must back international mediator Kofi Annan's detailed plan for a political transition.
Clinton arrived in St Petersburg for a meeting on Friday with Russian Foreign Minister Sergei Lavrov, with their countries deeply divided over Syria and increasingly at odds over everything from anti-missile defense to human rights.
Clinton and Lavrov are due to attend a meeting of the five permanent members of the U.N. Security Council on Syria in Geneva on Saturday, but on Thursday gave sharply different accounts of what they expected it to achieve.
Lavrov, whose government has been the main supporter of Syrian President Bashar al-Assad as he seeks to crush a widening rebellion, told reporters the meeting "must set the conditions for the end of violence and the start of an all-Syria national dialogue, and not predetermine the contents of this dialogue".
But Clinton, who agreed to attend the meeting on condition that it sets out a framework for Assad to step down, disagreed sharply.
"It was very clear from the invitations that were extended by Special Envoy Kofi Annan that people were coming on the basis of the transition plan that he presented," Clinton told reporters in Latvia before heading to St Petersburg.
Diplomats at the United Nations say Annan will seek backing in Geneva for a proposal that does not explicitly stipulate that Assad must step down, but does call for a unity government that would exclude figures who jeopardize stability.
The United States and its allies say Assad - whose crackdown on the 16-month old rebellion has killed more than 10,000 people, according to U.N. estimates - should have no role in any future political arrangements. Syria says more than 2,600 members of the security forces have been killed.
Clinton said that while the transition should be "Syrian-led", it must meet certain standards.
"We certainly believe that you have to have a transition that complies with international standards on human rights, accountable governance, the rule of law, equal opportunity for all people of Syria," Clinton said. "This (Annan) framework lays out how to arrive at that."
Annan, struggling to save a disintegrating peace plan for Syria, called the meeting as a way of bringing together the five veto-holding members of the U.N. Security Council, including Russia and China, with prominent neighboring states such as Turkey to discuss the way forward on Syria.
Russia, joined by China, has thus far used its veto to block Western- and Arab-backed moves for tougher U.N. action on Damascus, long a key regional ally and a big buyer of Russian arms.
Annan did not invite Iran, Syria's main ally in the region. Moscow says Iran should play a role in resolving the crisis but the United States rejected the idea.
The Syria impasse has further clouded U.S.-Russia ties, where the Obama administration's early "reset" of relations with the Kremlin has soured into a series of testy exchanges reminiscent of the Cold War.
Russian reacted with fury this week after a U.S. Senate panel approved a bill that would penalize Russian officials for human rights abuses, warning Washington that such sanctions would force Russia to respond in kind.
Russia has also strongly opposed U.S. plans for a new missile defense system, saying that interceptors that the United States and NATO are deploying as part of the system will be able to destroy Russian warheads in flight by about 2018, upsetting the post-Cold War balance of power.
The gloomy state of the Russia relationship has left Obama open to election year salvoes from his Republican rival Mitt Romney, who has accused Obama of being soft on Moscow and failing to deliver on early hopes for more cooperation.
Despite the diverging positions, U.S. officials remain hopeful that the escalating carnage and very real threat of Syrian civil war may eventually persuade Russia to drop its support for Assad - a key condition for opposition fighters battling Assad's soldiers in the towns and villages.
Reporting By Andrew Quinn; Editing by Kevin Liffey