Stoltenberg hailed "Biden's focus on rebuilding alliances", NATO said, following four years of US president Donald Trump who lashed out at long-standing allies.

Stoltenberg underlined that "NATO is the place where Europeans and Americans meet every day and that together, we can face challenges that none of our nations can face alone."

He and Biden "agreed to work together on preparing the NATO Summit in Brussels later this year, where leaders will take decisions to make our strong Alliance even stronger," NATO said.

They discussed common challenges like "countering international terrorism, including in Afghanistan and Iraq, dealing with a more assertive Russia, and addressing the implications for our security of the rise of China," the statement said.

The pair pledged to cooperate on tackling climate change and the coronavirus pandemic, while calling for maintaining the "momentum for increased defence spending, to keep our nations safe in an unpredictable world," it said.

The next NATO summit is due to take place in Brussels, seat of the alliance, but timing depends on fighting the pandemic.

Charles Michel, head of the European Council, also proposed to Biden to organise a special gathering with all the leaders of the European Union.

NATO and EU institutions are all based in Brussels and the idea is to organise these two meetings at the same time, a diplomat said.