US President Donald Trump has condemned bomb threats against US Jewish community centres in recent weeks.
“We have to fight bigotry, intolerance and hatred in all of its very ugly forms,” he said while visiting an African-American museum in Washington.
The FBI is investigating the most recent spate of threats on Monday.
Mr Trump was attacked last month when a statement released in his name to commemorate Holocaust Remembrance Day failed to use the word “Jew”.
There was also outcry that the statement did not recognise Jewish people were specifically targeted by Nazi state-sponsored anti-Semitic propaganda.
The president confronted the issue on Tuesday after touring the National Museum of African American History and Culture in the nation’s capital.
“The anti-Semitic threats targeting our Jewish community and community centres are horrible and painful,” he said.
On Monday 11 Jewish community centres across the country, including in the Houston, Chicago and Milwaukee areas, reported receiving hoax bomb threats.
Last week, 27 Jewish community centres in at least 17 US states received such hoax threats.
No bombs were found at any locations, and normal services resumed following building evacuations.
Police in the state of Missouri have meanwhile opened an investigation after more than 170 headstones were damaged at a Jewish cemetery in St Louis, Missouri, on Monday evening.
In the Canadian city of Toronto, Mayor John Tory has condemned anti-Semitic hate notes left outside the homes of Jewish residents.