Working smoke alarms are being credited with saving the lives of three people who were sleeping when a fire broke out in their row home in Ottawa's east end early Monday morning.

Firefighters say the residents managed to make it out of the burning home on Carson Road before fire crews arrived at about 3:30 a.m.

The fire started in a bedroom on the second floor, where it was contained.

Firefighters say the blaze caused extensive smoke damage to the entire unit, preventing the three adults who live there from returning home. Damage to the building is estimated at $200,000.

The displaced residents are now in the care of the Salvation Army and Red Cross.

Firefighters say the blaze is an example of how working smoke alarms can save lives.

The cause of the fire remains under investigation.