GLASSPORT, Pa. -- An overnight fire is causing concerns for people living in Glassport. This is the fourth suspicious fire in just the past few weeks.

Flames were reported at a vacant house along Maryland Avenue just after 3:30 a.m. Thursday.

Glassport's fire chief said the blaze started in the basement and quickly spread to upper floors. Firefighters from five communities managed to keep the flames from spreading.

The Allegheny County fire marshal and Glassport police and fire officials are trying to figure out who set four fires in their community in the past two weeks.

All fires have all been in vacant houses and fire officials consider the fires suspicious.

No injuries have been reported.