US President Donald Trump on Monday branded Democrats a “disgrace” for holding impeachment proceedings while he attends a NATO summit in Britain and rejected participating in what he called “a hoax.”

House Democrats are due to move forward this week with their case to make the real estate mogul only the third president ever to be impeached.

The House Judiciary Committee will hold a hearing on Wednesday at which experts will weigh whether Trump’s alleged wrongdoing in pressuring Ukraine to investigate domestic political foe Joe Biden meet the constitutional bar for impeachment.

“The Democrats, the radical-left Democrats, the do-nothing Democrats, decided when I’m going to NATO — this was set up a year ago — that when I’m going to NATO, that was the exact time,” Trump said angrily on departing the White House.

“It’s an absolute disgrace what they’re doing to our country,” he said before his plane touched down in London.

“The whole thing is a hoax. Everybody knows it.”