Five Jewish community centers across the United States and Canada were evacuated following bomb threats during the Purim holiday on Sunday, the latest incidents in a wave of harassment targeting Jewish institutions across North America.

The targets of Sunday’s bomb threats included the Jewish Community Center of Rochester, the Indianapolis Jewish Community Center, the Evelyn Rubenstein Jewish Community Center of Houston, the Samson JCC of Milwaukee, and the JCC of Greater Vancouver in Canada.

A total of 154 such threats have been made against Jewish community centers across North American since the beginning of the year. Some centers, including the JCC of Rochester, have been evacuated for multiple threats. The Rochester JCC was evacuated less than a week ago for a similar threat, while the Rubenstein JCC in Houston was threatened twice in three weeks.

Federal investigators have attempted to clamp down on the systematic harassment of Jewish institutions, but only one arrest has been made since the spike in threats two months ago.

On March 3rd, FBI agents arrested 31-year old Juan Thompson, a left-wing journalist the bureau says is responsible for at least eight threatening calls to Jewish centers around the country.