A predawn explosion rocked the Malmo, Sweden, neighborhood outside the city’s Jewish community center Friday, with residents reporting hearing loud noises prior to the blast.

According to news reports, witnesses told police they saw two people drive away shortly after the explosion; a few hours later, authorities had taken two unidentified men in for questioning.

Rabbi Shneur Kesselman, director of Chabad-Lubavitch of Malmo, said that the two suspects have denied any connection to the attack. The center, which sustained minimal damage to its exterior, houses the Chabad center and a kindergarten.

“It is bullet-proof glass,” he said. “They managed to break it, but not break through it.”

In April, the U.S. Special Envoy to Monitor and Combat Anti-Semitism Hannah Rosenthal expressed concern about a series of anti-Semitic incidents in Malmo, calling the situation “not just serious, but acute.”

“In Malmo, the synagogue, which is a place for the community to gather and worship, has become a site of anti-Semitic slurs and vandalism,” despite enhanced security, she said.

“People are upset,” Kesselman, who has personally been attacked numerous times since arriving in Malmo in 2004, said after the latest attack.

The rabbi happens to be waiting for his car to be repaired after it was vandalized two weeks ago.

“We are going on as usual,” he said. “Thank G‑d, we are all okay.”