US President Donald Trump was left in the dark when the lights went out as he made an address at the White House.

Mr Trump was saying he has “full faith” in the US intelligence agencies in the aftermath of his Helsinki news conference when the lights in the Cabinet Room dimmed and briefly went out, leaving the room mostly in darkness.

The president joked: “Whoops, they just turned off the lights. That must be the intelligence agencies.”

As the lights were quickly switched on, Mr Trump asked if members of his Cabinet, politicians and the media were OK.

“That was strange. But that’s OK,” he said.

Mr Trump was trying to make clear after his meeting with Russian President Vladimir Putin that he fully supports the US intelligence community and its finding that Russia interfered in the 2016 elections.

His remarks came during a meeting with vice president Mike Pence, treasury secretary Steven Mnuchin and several members of Congress.

The president was discussing Republican tax legislation that is expected to be considered in September.