US President Donald Trump has said musical performances celebrating the country's 250th birthday should be called off after several artists dropped out, citing the event's affiliation with the White House.

"Cancel it," he said in a post on Truth Social, calling the slated performers "overpriced" and "boring".

As of Sunday, only a few musical acts were still scheduled to perform out of nine featured artists originally announced on Wednesday. Martina McBride, The Commodores, Young MC and Bret Michaels dropped out.

Vanilla Ice and Milli Vanilli are still on for 26 June, as is Flo Rida on 2 July. Trump said he is now considering replacing the event with a "Make America Great Again rally".

Freedom 250, the group behind the Great American State Fair concert series, was launched last year by the Trump administration and the president appointed its CEO - but it says the event is non-partisan.

The White House is partnering with Freedom 250 on the fair, part of a "series of once-in-a-generation events for America's momentous anniversary".

Freedom 250 announced on Saturday that the president will headline the fair's opening ceremony.

"As the visionary behind the Great American State Fair, we are excited to announce that President Trump will personally kick off this historic celebration on Wednesday, June 24 in an opening ceremony celebrating America's 250th birthday," spokeswoman Danielle Alvarez said.

Congress created an organisation a decade ago to arrange and oversee events commemorating the country's 250th birthday, America250.

That group is led by appointees from both parties, Democrat and Republican, and has its own events. They include 4 July celebrations in New York City, Philadelphia and California, and block parties across the US.

Trump signed an executive order last year establishing his own taskforce "to provide a grand celebration worthy of the momentous occasion of the 250th anniversary of American Independence". The taskforce created Freedom 250 "to achieve that ambitious mission", the White House site states.

Freedom 250 unveiled the artists on Wednesday for the 16-day series of events planned on the National Mall in Washington DC between 25 June and 10 July.

Country singer McBride had been scheduled to perform the first night. Poison frontman Michaels was scheduled on 3 July, the eve of Independence Day. Both cancelled.

Young MC, best known for his 1989 hit Bust a Move, said on his social media that artists had not been told about any "political involvement with the event" and that he looked forward to performing in DC in the future at an event that was "not so politically charged".

McBride said in a statement on X that she was "presented with an opportunity to perform at a nonpartisan event but that turned out to be misleading".

But Vanilla Ice, whose real name is Robert Matthew Van Winkle, said: "This is not a political platform. This is celebrating America's birthday," in a caption to a video post on his Instagram account.

One half of Milli Vanilli's public-facing duo, Fab Morvan, said he will also perform as scheduled. The voices behind Milli Vanilli's music said in a statement on X that they will not be performing.

Trump said in a post on Truth Social that he had heard artists were getting "the yips" - a term used in golf for involuntary spasms or freezes that impact a swing. He said he was thinking of appearing himself at the same time and location.

"I am ordering my Representatives to look at the feasibility of doing an AMERICA IS BACK Rally on Wednesday, Washington, DC, same time, same location. Only Great Patriots invited," he wrote, calling himself the "Number One Attraction anywhere in the World" and saying he "gets much larger audiences than Elvis in his prime".

He later doubled down, saying he wanted to replace the planned fair altogether with a rally.

"We should have a giant MAKE AMERICA GREAT AGAIN RALLY, for 250, instead of having overpriced singers, who nobody wants to hear, whose music is boring, and yet who do nothing but complain," he said.

The White House is backing a number of events organised by Freedom 250 to mark the anniversary of US independence.

They include a UFC fight on its South Lawn, the Great American State Fair in June and July, and a Grand Prix race in the US capital in August.

The US will also release a limited number of commemorative passports that feature a portrait of Trump.