Donald Trump has denounced recent threats against Jewish community centres in the US as "horrible" and "painful".
The US president said the threats are a "very sad reminder of the work that still must be done to root out hate and prejudice and evil".
He was speaking after touring the newly opened National Museum of African American History and Culture in Washington.
"This tour was a meaningful reminder of why we have to fight bigotry, intolerance and hatred in all of its very ugly forms," Mr Trump said.
His comments about threats at Jewish community centres across the country marked the first time he had directly addressed a wave of anti-Semitism and followed a more general White House denouncement of "hatred and hate-motivated violence".
That statement earlier on Tuesday did not mention the community centre incidents or Jews.
Mr Trump "has made it abundantly clear that these actions are unacceptable", the statement said.
The FBI said it is joining the Justice Department's Civil Rights Division to investigate "possible civil rights violations in connection with threats" to the centres.
On Monday, Mr Trump's daughter Ivanka wrote on Twitter: "We must protect our houses of worship & religious centers," and used the hashtag #JCC.
She converted to Judaism ahead of her 2009 marriage to Jared Kushner.
She joined her father at the African American museum tour.
The White House was criticised by Jewish groups last month after issuing an International Holocaust Remembrance Day statement that did not mention Jews.
On Monday, 11 Jewish community centres across the country received phoned-in bomb threats, according to the JCC Association of North America.
Like three waves of similar calls in January, the threats proved to be hoaxes, the association said in a statement.
All of the affected centres have returned to normal operations.
Mr Trump said: "The anti-Semitic threats targeting our Jewish community and community centres are horrible and are painful and a very sad remainder of the work that still must be done to root out hate and prejudice and evil."