Washington: President Barack Obama on Friday abruptly altered the timing of his upcoming appearance at an international climate summit in Copenhagen, hoping to capitalise on steps by India and China and build a more meaningful political accord, the White House said.

The move means Obama will be at the summit on December  18, considered a crucial period when more leaders will be in attendance, as opposed to his scheduled stop in Denmark on Wednesday on his way to Nobel Peace Prize events in Oslo.

It also means that Obama will be squeezing in a separate, 10th foreign trip before Christmas a record pace of travel for a first-year president as a means to giving momentum to a deal aimed at combatting global warming.

Obama will now leave for Oslo late Wednesday, attend Nobel events Thursday and return to Washington on Friday.

Obama had said that he would travel to the Copenhagen conference if his appearance would help clinch a deal. His decision to go early to the two-week meeting was looked upon by many as a sign that an agreement was still a long shot.

But now with the US, India and China all with specific proposals on the table for the first time, a political agreement seems more likely. World leaders are no longer expected to reach a legally binding agreement, as had long been the goal, but are aiming for a deal that includes commitments on reducing emissions and financing for developing countries.

"There are still outstanding issues that must be negotiated for an agreement to be reached, but this decision reflects the president's commitment to doing all that he can to pursue a positive outcome," White House press secretary Robert Gibbs said in a statement. Gibbs said the US will have negotiators involved throughout the December 7-18 conference.

It is also possible that Obama could tack on another agenda item to his revamped, final trip of the year: the signing of a broad treaty with Russia to reduce both nations' nuclear arsenals. The White House had hoped that deal would be ready in time to coordinate it with his receiving the Nobel Peace Prize, but talks have not produced a final breakthrough.