WASHINGTON (AFP) - US President Barack Obama will hold talks Friday with Chinese Premier Wen Jiabao on the sidelines of a UN climate summit in Copenhagen, the White House said.

Obama, who was traveling overnight to the Danish capital to attend the final day of the UN talks aimed at hammering out a pact to combat climate change beyond 2012, will deliver remarks in the morning plenary session before holding a bilateral meeting with Wen, who will also address the summit.

Amid bitter wrangling between key players and warnings of failure to reach a deal, China and the United States -- the world's two biggest carbon polluters -- have brushed aside European calls for concessions on reducing greenhouse gas emissions, the thorniest issue of all at the talks.

Chinese Vice Foreign Minister He Yafei warned however on Thursday that countries must swiftly move to narrow their differences or face failure.

"Now there is only one day left. The negotiation has reached a critical point," He told reporters.

"We should not continue to dwell on these issues that are dividing us. We should narrow our differences, otherwise we are facing a failure."

US Secretary of State Hillary Clinton meanwhile took a thinly-veiled swipe at China when she accused emerging economic giants of backsliding on pledges to open their emissions controls to scrutiny, saying a lack of commitment on transparency could become a "deal breaker."

"There have been occasions in this past year when all the major economies have committed to transparency," Clinton told a press conference.

"Now that we are trying to define what transparency means and how we would both implement it and observe it, there's a backing away from transparency and that to us is something that undermines the whole effort that we're engaged in."