Donald Trump has described the Republicans' defeat in the midterm elections as “a giant step back in history”, in his bluntest public reaction yet to the result that handed Democrats control of both chambers of Congress.

“America took a giant step back in History with the results of the last Election,” the president wrote in a post on Truth Social on Sunday. “But have no fear, we will be back, BIGGER AND STRONGER THAN EVER BEFORE!”

The post came as Trump spent the weekend at his Mar-a-Lago home in Florida, his 31st visit to Palm Beach of his current term. He arrived on Friday, 6 November, with Secretary of State Marco Rubio and Stephen Miller, the longtime aide who has just been promoted to White House chief of staff, and rounded off the trip on Sunday with a visit to his Trump International Golf Club.

While in Florida, Trump also used social media to blame the Democrats' election sweep for sharp falls in the stock market. US markets fell heavily on 5 November, with the technology-heavy Nasdaq Composite Index dropping 5.5 per cent. Analysts quoted in the US press said the reasons for the losses were more complex than the election result alone, pointing to uncertainty over data centres and artificial intelligence spending.

The president has also signalled that more staff changes could follow the departure of his chief of staff, Susie Wiles. In an interview with CBS News' 60 Minutes, recorded on Friday and broadcast on Sunday, Trump was asked whether he expected to dismiss anyone from his team after the midterm defeat.

“I do,” he replied. “A little bit. I love my Cabinet. I think they're good. But I'll be doing maybe a few changes. I don't want to mention who.”

Wiles is leaving the White House and moving to the president's political operation. Trump announced on Friday that Miller will replace her as chief of staff from Monday, 9 November. A day earlier, Harmeet Dhillon, the assistant attorney general for the Justice Department's Civil Rights Division, resigned. She later said she had submitted her resignation three weeks earlier and that Wiles had asked her to wait until after the midterm elections before making it public.

Trump's first formal speech since the 3 November election came at the Kennedy Space Center in Florida, where he dismissed concerns about the cost of living and pointed to a report from his administration saying the economy added 165,000 jobs in October. He argued that the election result simply reflected the fact that he had not been on the ballot.

“By the way, I was not on the ballot, just in case you had any questions,” he said. “If we were on the ballot, we would have won, but we weren't.”

During the same speech, he announced that the former space shuttle landing strip at the Kennedy Space Center would become the venue for a new air and space show by 2028, which he said would top the shows in Paris and Dubai. He also said NASA would launch the first nuclear-powered spacecraft to Mars within two years, followed by a permanent presence on the Moon.

The president also used his weekend posts to rail against the incoming Democratic congressional majority, accusing it of threatening administration officials with investigations. He again raised the Alaska Senate race, where votes are still being counted and Democratic rival Mary Peltola is in the lead over the Republican candidate Daniel Sullivan.

Calls for the removal of senior administration officials are growing on both sides. Republican Congressman Thomas Massie of Kentucky has said he plans to call for a vote to impeach War Secretary Pete Hegseth, whom he blames for the war with Iran. Hegseth hit back in a video posted on X, calling the move a “sham” article of impeachment from a “disgruntled, defeated congressman”.

In his 60 Minutes interview, Trump reiterated his confidence in Hegseth and claimed credit for military successes, saying: “Look, we've won two wars. We've won Venezuela and taken out billions and billions and billions of dollars already. We won that war in less than one hour.” Asked whether he credited Hegseth for those claimed victories, he replied: “No. But he was a part of it.”

The midterm result was the Republicans' worst showing since the post-Watergate election of 1974, and Democrats are now poised to win more than 250 House seats and 54 Senate seats, as well as 30 governorships. With a Democratic Congress taking its seats in January, Trump faces two years of investigations and legislative opposition in the final part of his presidency.