The U.S. Senate on Tuesday called on the Trump administration to take a more aggressive approach to counter the growing number of anonymous bomb threats against Jewish organizations across the country.

All 100 senators said in a letter addressed to Attorney General Jeff Sessions, FBI Director James Comey and Homeland Security Secretary John Kelly that the incidents are becoming more frequent and failure to take swift action places innocent people at risk.

“We write to underscore the need for swift action with regard to the deeply troubling series of anonymous bomb threats made against Jewish Community Centers (JCCs), Jewish day schools, synagogues and other buildings affiliated with Jewish organizations or institutions across the country,” the senators wrote.

The letter came as the Anti-Defamation League and several Jewish community centers across the U.S. received a new round of bomb threats, adding to the scores that have been plagued with since January.

Federal authorities have been investigating more than 120 threats against Jewish organizations in three dozen states since Jan. 9 as well as a wave of vandalism at Jewish cemeteries. Over the course of Monday evening and Tuesday, there were eight emailed or phoned-in bomb threats in six states plus Ontario, the JCC Association of North America said.

Bomb threats were made to Jewish centers in upstate New York, Wisconsin, Oregon, a synagogue in Rhode Island and a school in Illinois. The Anti-Defamation League received threats to its offices in New York, Atlanta, Boston and Washington D.C., as well as other offices in Florida and Maryland.

On Friday, Missouri resident Juan Thompson was arrested on a cyberstalking charge and accused of making at least eight of the threats nationwide, including one to the ADL. Authorities said Thompson was trying to harass and frame his ex-girlfriend by pinning the threats on her.

The Associated Press contributed to this report.