Jens Stoltenberg told journalists Trine Eilertsen and Harald Stanghelle he has enjoyed drinking sessions with Merkel on several occasions, saying “let’s put it this way: she isn’t the first to leave”.
“She drinks white wine, and I drink beer,” he said.
“I am very impressed by her stamina. We had a very good evening in Stralsund [a German coastal town where Merkel hosted a summit in 2012]. ”
He attributed their strong friendship to long, gruelling nights developing policies such as climate change.
“That gives you a kind of chemistry, a kind of closeness. Obama is also someone I have met many times. I think it was those two who supported me as a candidate for [Nato] general secretary,” he said.
Mr Stoltenberg was at first hesitant when asked by journalists which political heavyweights he enjoyed spending time with.
“That’s a dangerous question, because it implies I have bad chemistry with others,” he said.
“Political leaders are mainly sociable, nice people, otherwise they wouldn’t have been elected,” he said. “It’s easy to make friends.”
The Nato secretary general said his friendship with Merkel goes back six years to their meeting in Denmark, and they have drunk together “many times”.
Meanwhile, Russia poses no immediate threat to Nato countries and the military alliance still hopes bilateral relations will improve, Stoltenberg said. Russia had been willing to use force to change borders in Europe, he said during a visit to his native Norway, pointing to Crimea, east Ukraine and Georgia as examples.
“What we see is more unpredictability, more insecurity, more unrest. But I believe we don’t see any immediate threat against any Nato country from the east,” he told NRK public radio.
Nato has repeatedly criticised Moscow’s involvement in the Ukraine conflict and demanded it fully endorse a ceasefire agreement there. Russia denies providing troops or arms to support separatists rebels in eastern Ukraine.
The Ukraine conflict has in particular unnerved Latvia, Lithuania and Estonia, the only parts of the former Soviet Union that have joined Nato. The Baltic states are small and isolated from the rest of the EU, and have Russian-speaking minorities which President Vladimir Putin said last year gives Moscow the right to intervene with military force.