US fully committed to UN climate talks: top US negotiator

The US administration is "fervently engaged" in UN talks to forge a global climate treaty but cannot rescue the troubled process on its own, its top climate negotiator said Sunday.

The entry of the new US team into negotiations involving more than 190 states and riven by deep divisions between rich and developing countries has generated huge expectations, sharpened by the contrast with Obama's predecessor.

George W. Bush had rejected the Kyoto Protocol, whose provisions expire in 2012, and nearly torpedoed the 2007 "Bali Roadmap" agreement that set a December 2009 deadline for a new deal.

Stern addressed more than 2,500 participants at the opening plenary session of the UN forum.

"We are very glad to be back," he said to enthusiastic applause.

Reactions were broadly positive, even from nations that remain critical of parts of Obama's climate plan.

"I am very glad that the US is reengaging -- that is a very good sign," - top Chinese negotiator, Su Wei