President Trump and British Prime Minister Theresa May walk together on May 26 during the Group of Seven summit in Taormina, Italy. (Luca Bruno/AP)

BRANCHBURG, N.J. — President Trump's plans for a state visit to Britain later this year appear to be up in the air, as he faces a backlash from across the pond for his criticism of London Mayor Sadiq Khan in the immediate aftermath of the June 3 terrorist attack in which eight people died.

Due to previous comments Trump was already unpopular in the United Kingdom, and a visit of any sort could prompt large protests. The Guardian newspaper, quoting anonymous individuals, reported that Trump recently told British Prime Minister Theresa May in a phone call that he does not want to go forward with a state visit until the British people support such a visit. The White House call was made “in recent weeks,” according to a 10 Downing Street adviser who was in the room, the Guardian wrote. The statement surprised May, according to those present.

While the White House has said a visit would come later this year, the exact schedule remains unannounced. At least publicly, Trump and May are acting as if the trip is still on.

White House press secretary Sean Spicer labeled the Guardian report as “false,” without citing specifics, and a White House spokesman, Raj Shah, said Sunday: “The president has tremendous respect for Prime Minister May. That subject never came up on the call.” Shah did not specify which call he was referring to.

A spokeswoman for the prime minster said: “The queen extended an invitation to President Trump to visit the U.K., and there is no change to those plans.”

May, herself, has her hands full right now, with her party losing its controlling majority in Parliament following a snap election that she called in hopes of solidifying her position. To maintain power, the Conservative Party has to strike a deal with the small Democratic Unionist Party in Northern Ireland, but there is speculation that even if such a bargain is reached, May could still be forced to resign by members of her own party.

If May is forced out, Trump would lose an international ally. While many of May's European counterparts have forcefully challenged Trump and kept him at a distance, she has tried to foster a productive relationship with the unpopular president — a move that could have contributed to the election losses.

For more than a year, Trump and Khan have publicly debated Trump's calls for a ban that would block Muslims or people from several predominantly Muslim countries from entering the United States. Khan, a human rights lawyer and practicing Muslim whose parents are from Pakistan, has repeatedly accused the president of having an “ignorant view of Islam.” Soon after the Saturday night attack on London Bridge, Trump tweeted about the attack and used it to promote his travel ban, which is being blocked by the courts. Trump also accused Khan of not taking the threat of terrorism seriously enough, citing a quote from Khan that had been taken out of context.

The president’s decision to lash out at the London mayor as his city attempted to recover from the June 3 attacks was widely questioned. Trump’s tweets were widely mocked in Britain, where the overwhelming mood is one of unity against terrorism and praise for security services. At the time, Jeremy Corbyn, leader of the opposition Labour Party, accused the president of lacking “grace” and “sense.” May came to Khan’s defense, telling journalists that the mayor was “doing a good job, and it’s wrong to say anything else.”

William Booth contributed to this report.