Two months before he makes a controversial trip to London, US President Donald Trump compared a hospital in the UK capital to a “war zone,” suggesting the country’s anti-gun culture is contributing to a surge in stabbings.

“I recently read a story that, in London, which has unbelievably tough gun laws, a once very prestigious hospital — right in the middle — is like a war zone for horrible stabbing wounds,” Trump told the annual gathering of National Rifle Association in Dallas on Friday, without identifying the source of his information. The hospital, which he didn’t name, had “blood all over the floors” from knife crime, he said.

“They say it’s as bad as a military war-zone hospital,” Trump told the US pro-gun rights’ group. “Knives, knives, knives. London hasn’t been used to that. They’re getting used to it. It’s pretty tough.”

Trump is scheduled to visit the city on July 13 after several stop-starts since his inauguration. In January, he said he had “cancelled” a trip to formally open the new US embassy in London because he thought the building was “a bad deal.”

The president’s latest comments add fire to the verbal derision that has stoked public anger in the UK after he lambasted the government’s response to terrorist attacks, criticised London Mayor Sadiq Khan and re-tweeted propaganda by a fringe far-right UK political group. He also reprimanded Prime Minister Theresa May for condemning his re-tweets of Britain First, saying she should mind her own business.

In February, he took aim at the country’s much-venerated National Health Service, saying it’s “going broke and not working.”

London has experienced a surge in violent crime this year, with 52 people killed in the first 100 days of 2018, according to the BBC. Murders in the city rose to 153 in the year to the end of March, from 101 the previous year, according to the Metropolitan Police.

But the magnitude of violent crime is still well below that of the US, where there were an estimated 17,250 murders in 2016, according to data compiled by the FBI’s Uniform Crime Reporting Programme. In New York City that year, the bureau and the New York Police Department reported 335 homicides.

From March 2015 to March 2016, there were 571 homicides in England and Wales, according to Britain’s Office for National Statistics.

Trump’s speech in Dallas was his fourth in a row to the group’s annual convention. The NRA spent $30 million (Dh110.1 million) in support of Trump’s 2016 campaign, lending him credibility with some conservatives.