Merkel – only the second German leader to address Congress since Konrad Adenauer in 1957 – received a standing ovation and sustained applause, said the agency.

Before her address on Capitol Hill, Merkel held talks at the White House with President Barack Obama, who hailed her as an "extraordinary leader".

"Germany has been an extraordinarily strong ally on a whole host of international issues," Mr Obama said, Merkel at his side in the Oval Office, according to the BBC.

Obama praised the German chancellor – re-elected in September at the helm of a centre-right coalition – for her leadership on "the issue of climate change".

As the Copenhagen summit approaches, Merkel is likely to push for stronger US backing for a deal on tackling climate change.

"The fight against climate change is one of the most urgent tasks worldwide," she said in a video message over the weekend.