British Prime Minister Theresa May | Tolga Akmen/AFP via Getty Images Theresa May condemns ‘completely unacceptable’ Trump tweets amid US racism row US president says 4 congresswomen should ‘go back’ to ‘crime infested places from which they came.’

Theresa May denounced Donald Trump over the U.S. president's online attacks on Democratic congresswomen of color.

Trump tweeted Sunday that the four women, who "originally came from countries whose governments are a complete and total catastrophe," should "go back" and fix issues in those countries before telling him how to run the U.S. government.

His tirade was directed at Alexandria Ocasio-Cortez, Rashida Tlaib and Ayanna Pressley, who were born in the U.S., and Ilhan Omar, who arrived in the country as a refugee from Somalia aged 12.

A Downing Street spokesman said Monday morning: "The prime minister’s view is that the language used to refer to these women was completely unacceptable.”

The women targeted have accused Trump of racism for saying: “So interesting to see 'Progressive' Democrat Congresswomen, who originally came from countries whose governments are a complete and total catastrophe, the worst, most corrupt and inept anywhere in the world (if they even have a functioning government at all), now loudly and viciously telling the people of the United States, the greatest and most powerful Nation on earth, how our government is to be run.

“Why don’t they go back and help fix the totally broken and crime infested places from which they came. Then come back and show us how it is done.

“These places need your help badly, you can’t leave fast enough.”

Asked whether May considers the remarks racist, her spokesman refused to comment.

Democrats have condemned the president's actions but Republican Party representatives have so far refused to weigh in.