Rutte, a stalwart backer of Ukraine, noted he has worked before with former US president Donald Trump, the Republican candidate, who has voiced scepticism over funding for Kyiv.

"I'm not worried. I know both candidates very well. I worked for four years with Donald Trump," said Rutte, a former Dutch prime minister, shortly before he becomes the next NATO secretary general.

On the campaign trail, Trump has threatened not to protect NATO members who do not spend enough on defence and promised he can cut a quick deal with Russian President Vladimir Putin to end the war in Ukraine.

Rutte, who is widely credited with rescuing a 2018 NATO summit by talking Trump round on defence spending, also praised Vice President Kamala Harris, the Democratic nominee, for having a "fantastic record".

"She's a highly respected leader," he said.

Ahead of a handover ceremony in Brussels, departing NATO boss Jens Stoltenberg said the military alliance was in "safe hands" with Rutte.

"He knows how to make compromises, create consensus, and these are skills which are very much valued here at NATO," Stoltenberg said.

"NATO will be in safe hands."