A security guard at Detroit Receiving Hospital discovered a man was holding a grenade in his hand with the pin pulled out, after the man set off an entrance metal detector Saturday evening, The Detroit Free Press reported.

The two wrestled for the grenade while staff rushed to evacuate the emergency room, the newspaper said. After other officers arrived and the man was subdued, another grenade was discovered in his possession.

Police handed the pinless grenade over to a bomb squad, and the man was placed under psychiatric evaluation in the hospital's crisis unit.

The emergency room was reopened about 30 minutes later.