UPDATE 1-Obama backs two-step plan to reach climate deal

(Adds details and background)

SINGAPORE, Nov 15 (Reuters) - U.S. President Barack Obama has backed a plan by the host of next month's climate change talks in Copenhagen to seek a political deal and leave legally binding decisions for later, a U.S. official said on Sunday.

"There was an assessment by the leaders that it was unrealistic to expect a full internationally legally binding agreement to be negotiated between now and when Copenhagen starts in 22 days," a top U.S. negotiator, Michael Froman, told reporters.

With Kyoto's first phase set to run out in 2012, the Dec. 7-18 Copenhagen talks are seen as the last chance for all countries to agree on painful measures needed to ease the pace of climate change.

The aim of the U.N. meeting is to set ambitious targets for cutting greenhouse gases, but also to raise funds to help poor countries tackle global warming.

Danish Prime Minister Lars Lokke Rasmussen, host of the Copenhagen talks, told Reuters earlier this month he was hoping for a political deal to replace the Kyoto Protocol and had invited top world leaders to the meeting to agree it.

However, he said final, legally binding decisions would have to be taken later.

Froman was speaking after a breakfast meeting of leaders at an Asia Pacific Economic Cooperation (APEC) meeting in Singapore, the last major gathering of global decision-makers before Copenhagen.

"There was widespread support among the leaders that it was important that Copenhagen be a success, that there be the achievement of real concrete progress in Copenhagen with operational impact," Froman said. (Reporting by Caren Bohan; Writing by John Chalmers; Editing by David Fogarty)