LEHI, Utah (AP) — An early morning explosion in a Utah apartment injured two people and led to the temporary relocation of 90 families in the building because the sprinkler system was damaged, officials in Lehi said Tuesday.

The explosion, which police called “suspicious,” happened just after 4 a.m., spokesperson Jeanteil Livingston said. The couple in the apartment suffered minor injuries and were treated at the scene. No other injuries were reported.

The explosion caused damage inside the apartment and to the building's fire sprinkler system, leading to water damage in the apartment and some apartments below it, Livingston said.

Ninety families living in the Lehi Tech Apartments building were relocated to other units while water damage is cleaned up and the sprinkler system repaired. It's not known how long that will take, Livingston said.

The cause of the explosion is under investigation.

Lehi is a city of about 95,000 people between Salt Lake City and Provo.