US President Donald Trump has reacted to mounting pressure and said that anti-Semitism "has to stop" as he spoke out after a wave of Jewish hate crimes.

At a bad-tempered press conference last week, Trump was asked by a Jewish reporter about an increase in anti-Semitism but the president told the reporter to sit down and accused him of asking a misleading question.

But during a tour of the National Museum of African American History and Culture on Tuesday (21 February), Trump told MSNBC: "Anti-Semitism is horrible and it's going to stop and it has to stop.

"This tour was a meaningful reminder of why we have to fight bigotry, intolerance and hatred in all of its very ugly forms.

"The anti-Semitic threats targeting our Jewish community and community centres are horrible and are a painful and a very sad reminder of the work that still must be done to root out hate and prejudice and evil."

The president has previously been accused of not speaking out strongly enough against anti-Semitism. His comments came as bomb threats against institutions across the US resulted in the closure of 11 Jewish community centres while investigations were carried out.

Trump had been asked to speak out firmly against anti-Semitism by a number of political heavyweights, including former rival Democrat Hillary Clinton. She asked the president to make a comment after the gravestones of 170 Jewish people were knocked down in a cemetery in Missouri.