By Andrew MacAskill and Kate Holton

LONDON (Reuters) - British Prime Minister Keir Starmer on Sunday dismissed calls to cancel the offer of a state visit to U.S. President Donald Trump after his extraordinary row with Ukrainian leader Volodymyr Zelenskiy at the White House.

Starmer at a meeting in Washington last week used a mixture of flattery and the invitation from the royal family for an unprecedented second state visit to try to win a commitment from Trump for a U.S. security guarantee to protect Ukraine if a deal to end the war with Russia can be reached.

Some British politicians, including the leader of the Scottish National Party (SNP), have called for the offer to be withdrawn after Trump accused Zelenskiy of not being grateful enough for U.S. support in Ukraine's war.

Asked if the state visit should be cancelled, Starmer criticised politicians who he said wanted to widen divisions with Washington at a time when Europe faces a "moment of real fragility".

"I'm not going to be diverted by the SNP or others trying to ramp up the rhetoric without really appreciating what is the single most important thing at stake here, we're talking about peace in Europe," Starmer told the BBC.

Starmer, unlike some leaders in Europe, has sought to avoid criticising Trump despite provocations on everything from Gaza to Ukraine and possible tariffs.

CEREMONIAL AFFAIR

The invitation from King Charles, handed to Trump by Starmer in the Oval Office before the world's media, would make the U.S. president the first elected political leader in modern times to be hosted for two state visits by a British monarch.

A state visit is a grand, ceremonial affair full of pomp and pageantry and usually includes a carriage ride and a lavish state banquet.

During the reign of the late Queen Elizabeth only three U.S. presidents were given full state visits: Barack Obama, George W. Bush and Trump.

Trump, whose mother was from Scotland, has spoken regularly about his admiration for the British royal family. Although the royals are meant to be apolitical, they are often deployed to try to secure favourable relations with world leaders.

Trump's first state visit in June 2019 lasted for three days, during which he attended a state banquet and had tea with Charles, who was then heir to the throne.

The leader of the SNP, John Swinney, said on Sunday "it is hard to believe" that the offer to Trump still stands.

An opposition Conservative lawmaker Alicia Kearns, previously the head of parliament's foreign affairs committee, also said that the visit should be paused until the U.S. had offered to provide the security guarantee to Ukraine.

A petition calling for the invite to be cancelled has attracted almost 70,000 signatures and some of the normally right-wing British newspapers have also been critical of Trump since his row with Zelenskiy. The Telegraph said he had been "undeservedly and disgracefully bullied".

(Editing by Ros Russell)