US President Donald Trump has questioned the legitimacy of the midterm election results in which Republicans suffered sweeping losses – days after saying he would accept the outcome.

“Does anybody really believe that this ‘Election’ was honest. How could the Polls be so wrong?” Trump wrote on Truth Social on Monday.

This appeared to contradict what he told the New York Times on election night that he was “absolutely willing” to accept the results.

Democrats retook both chambers of Congress in last week’s elections. State and local officials across the US said voting had been mostly problem-free.

Some key races, including Senate contests in Alaska and Mississippi, have yet to be called.

In the Truth Social post, Trump made vague claims about polling, voting “dumps”, and “machines” without providing specific evidence of error or wrongdoing.

He has previously attempted to cast doubts on the integrity of elections he has lost, although he himself was not on the ballot in the midterms.

“We would have won easily if I was on the ballot,” Trump told CBS News, the BBC’s US partner, after it was confirmed his party had lost both the Senate and the House.

As it stands, Democrats have won 54 US Senate seats and 254 US House seats, giving them comfortable majorities in both chambers even as counting continues in some races.