By Andrew Gray

BRUSSELS (Reuters) -The whole of NATO, including the United States, is "totally committed" to keeping Ukraine in the fight against Russia's invasion, alliance Secretary General Mark Rutte told Reuters in an interview on Wednesday.

Speaking at the end of a summit of NATO leaders in The Hague, Rutte also said nobody in NATO was naive about Russia and

all alliance members "have more or less the same assessment" of Moscow.

U.S. President Donald Trump's more conciliatory stance towards Russia in his efforts to bring an end to the war in Ukraine has prompted questions about U.S. commitments to Kyiv.

"The whole of NATO, including the United States, is totally committed to keep Ukraine in the fight, to make sure that if there is a peace deal, that peace deal - or the ceasefire - will be lasting, will be durable," Rutte said.

He said the clear direction of travel was that Europeans would be responsible for more of the military aid to Ukraine.

But he said the United States would still be "very much involved with intelligence-sharing, with also practical military support" including potentially air defence systems.

"I think there will still be a huge, big American involvement," Rutte said.

The Trump administration has also told Europeans that they must take over primary responsibility for their own security, rather than relying on the United States through NATO.

Rutte said this process would be possible as Europeans had committed to spending more on defence, and it would be "well-organised" to avoid any gaps that Russia could exploit.

"I've had these discussions in Washington over the last couple of months," he said.

"For years, the U.S. has said 'we have to pivot more towards Asia'. Now that the Europeans are stepping up, that also makes it possible," he said.

"You will see that what the U.S. is delivering to NATO in terms of capabilities will gradually come down. But there's also total clarity from the U.S. that they don't want any capability gaps to emerge in Europe," Rutte said.

(Reporting by Andrew Gray;Editing by Sudip Kar-Gupta and Sandra Maler)