A “gathering for healing” event at Temple De Hirsch Sinai in Seattle, Aug. 2, 2006.

Vandals scrawled graffiti claiming the Holocaust was ‘‘fake history’’ on an exterior wall of a Seattle synagogue, leading the rabbi to urge President Donald Trump to more forcefully denounce a wave of anti-Semitic incidents in recent months.

Seattle police said they were investigating the vandalism at Temple De Hirsch Sinai as a hate crime after an off-duty officer spotted it on Friday. ‘‘Holocaust is fake history!’’ read the spray-painted message, with each letter S written as dollar signs.

In Seattle, Rabbi Daniel Weiner linked the incidents to what he characterized as permissiveness toward white supremacy from parts of the electorate during the 2016 presidential election campaign.

‘‘A message needs to come from our president, not only decrying anti-Semitism but specifically indicting white supremacists and in particular those who support his candidacy,’’ Weiner said, also referring to the bomb threats, vandalism against Jewish cemeteries and aggression against Muslims, Sikhs and immigrants.

Weiner did not blame Trump or his administration directly but regretted ‘‘the tone that has been set throughout the campaign, ’’when white nationalists embraced the Trump campaign.

Threats called ‘despicable’

Trump has denounced the anti-Semitic incidents, notably at the start of his address to Congress on Feb. 28. Weiner welcomed the response, even though he said he was ‘‘disheartened that it took cajoling and there was such a delay.’’

After a wave of bomb threats on Tuesday, the Trump administration denounced them ‘‘in the strongest terms,’’ White House spokesman Sean Spicer said, promising to search for ways to stop them.

More threats came later in the week and into the weekend. Bomb threats were received on Sunday by Jewish community centers in Indiana, Texas, New York, Wisconsin, Illinois, and Vancouver, British Columbia, the Jewish Community Center Association of North America said. Sunday’s threats brought the total this year to 128 incidents at 87 community centers, the association said. So far, all have been hoaxes.

On Sunday, police evacuated a Jewish Community Center in suburban Milwaukee after a bomb threat – the center’s fourth within two months, Whitefish Bay police spokeswoman Jenny Heyden Said in a telephone interview.

Investigators said there was evidence some of the US bomb threats may be linked to similar incidents in Britain. The American incidents prompted all 100 US senators last week to ask the federal government to help Jewish groups enhance security.

More than 140 Jewish community center leaders also wrote to US Attorney General Jeff Sessions expressing frustration with the investigation.