An early-morning blast rocked the Dar Al Farooq mosque in Bloomington, Minnesota, on Saturday, as worshippers had just begun to gather inside for morning prayers.

No injuries were reported. The building sustained damage to its front, and photographs from the scene showed a large shattered window, singed blinds and charring around the outside.

Police said Saturday afternoon that a “preliminary investigation indicates the explosion was caused by a destructive device.”

They announced that the Minnesota office of the FBI would take the lead on the investigation. Agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives were also on the scene.

The explosion was reported to police around 5 a.m., and they found “smoke and some damage” upon arriving. Mike Hartley, deputy police chief in Bloomington, said there was no structural damage to the building, but he declined to elaborate on any damage inside.

In a news conference, Mohamed Omar, executive director of the mosque, said the explosion had occurred “in the direction of the imam’s room.”

He said one member of the congregation immediately ran outside to see what had happened, and “saw a truck fleeing from the parking lot.”

While police had not determined a motive, community members and interfaith leaders of various congregations responded to the episode as yet another attack on a Muslim place of worship.

“We’re here all together in order to defend the values of our country, the values of our faith, the values of our people,” said Hamdy El-Sawaf, president of the board of the Islamic Community Center of Minnesota. “No matter what happens, small or big, it will never scare us, it will never bring us to our knees. We’re here to help each other, to support each other.”

Omar was joined by dozens of community members, with some in the crowd holding signs of support proclaiming, “All are welcome here.”

“What I would say is an attack on a mosque is an attack on a synagogue, it’s an attack on a church, it’s an attack on all faith communities, so we stand with you, a million Protestants in Minnesota,” said the Rev. Curtiss DeYoung, chief executive of the Minnesota Council of Churches.

The mosque had recently been the target of harassment, receiving threatening and hateful messages, Omar told The Star Tribune.

“People talking about us, telling us, accusing us that we shouldn’t be here, that we are like a burden to the community or we are like harming it,” Omar said.