LONDON, July 15 -- British outgoing prime minister and prime minister candidates on Monday condemned remarks made by the U.S. President Donald Trump about a group of mostly American-born Democratic congresswomen, calling them unacceptable.

The spokesperson of the outgoing British Prime Minister Theresa May said on Monday that Trump's remarks on several minority Democratic lawmakers telling them to "go back" to the "places from which they came" are "completely unacceptable".

But the spokesperson declined to give further remarks on the issue.

Asked during a leadership debate on Monday night whether they agreed with the prime minister that the comments were unacceptable, both forerunner Boris Johnson and Foreign Secretary Jeremy Hunt, two candidates for the job of prime minister, said they did.

Johnson, who called the remarks "totally unacceptable", said: "Relations between the UK and the U.S. are incredibly important but if you are the leader of great multi-racial, multi-cultural society you simply cannot use that kind of language about sending people back to where they came from."

Hunt said it is not going to help the situation to use that kind of language about the president of the United States.

The development came one day after Trump ignited a Twitter war with several minority Democratic lawmakers.

"Why don't they go back and help fix the totally broken and crime-infested places from which they came," Trump said in a series of tweets targeting at four Democratic lawmakers who were ethnic minorities.

Three of the four were born in the United States and one moved to the United States as a child refugee.

The group of four lawmakers, sometimes known as "the squad" among peers, was often attacked by Trump for their progressive positions.