ZAGREB, Croatia (AP) — A flying object crashed overnight on the outskirts of the Croatian capital, Zagreb, triggering a loud blast but apparently causing no injuries, police said Friday.

Some media reports said that the mysterious object could be a drone that flew to the Croatian capital from the Ukrainian war zone hundreds of miles away. Others said it could be a small plane. The reports could not be immediately confirmed.

The police said they came to the scene of the explosion on the outskirts of Zagreb after calls from local citizens. They said they found a large crater and two parachutes in a wooded area. Some parked cars were damaged.

Photos from the scene show metal pieces of the wreckage spread on the ground and what seems to be a section of a wing. Police sealed off the area of the blast for investigation.

Witnesses quoted by the media said they first heard a large explosion that rocked the ground, then a foul smell.