US President Barack Obama and his French counterpart Francois Hollande on Friday voiced support for an "ambitious and durable" climate deal, amid questions about the legal status of any Paris accord.

"Both leaders emphasized their personal commitment to reach an ambitious and durable climate change agreement," the White House said in a statement after the two men held a telephone discussion.

Obama is expected to attend the talks, which begin in Paris on November 30 and aim to secure a deal staving off catastrophic levels of global warming caused by greenhouse gas emissions.

His call with Hollande comes after Secretary of State John Kerry raised eyebrows by suggesting the deal would not be legally binding.

Washington has long insisted the agreement not be made a formal treaty, which would require approval by the Republican controlled Congress that is unlikely to be forthcoming.

French Foreign Minister Laurent Fabius -- fearing backlash from other nations making costly commitments to cut emissions -- said Kerry's comments "could have been more fortunate."