Donald Trump spared Russia from tariffs because of ongoing negotiations to end the war in Ukraine, a senior aide to the president has said.

Kevin Hassett, the director of the National Economic Council, said it would be “inappropriate” to start a trade war with Moscow when “so many Ukrainian and Russian lives” were at stake.

The US has imposed tariffs on almost every one of its allies, including a 10 per cent levy on Ukraine.

Asked by ABC’s George Stephanopoulos why Mr Trump had decided to exempt Russia, Mr Hassett said: “There’s obviously an ongoing negotiation with Russia and Ukraine, and I think the president made the decision not to conflate the two issues.”

He went on to suggest that Moscow could eventually be hit by tariffs after negotiations had concluded.

“It doesn’t mean that Russia, in the fullness of time, is going to be treated wildly different than every other country,” Mr Hassett added.

Pressed on why allies such as Canada and Mexico were not granted similar exemptions, Mr Hassett said it would not be “appropriate to throw a new thing into these negotiations right at the middle of it”.