London fire officials say damage is estimated at $300,000 after a blaze at a seven-storey apartment building in south London.

Crews were called around midnight to 30 Conway Dr. for a fire in an apartment on the top floor.

Colin Toth, a London fire investigator, says an apartment resident, "Quickly jumped into action and isolated his unit and started knocking on doors on the seventh floor, waking everybody up because most people were sleeping at this time - and assisted in evacuating everybody safely from the building."

Only one unit was damaged extensively by fire, damage to 16 other units directly below was caused by water.

Officials say there were no injuries, but about two dozen people were displaced by the fire.

"We were all pretty scared. My main concern was obviously my girls. So I was trying, more or less, to keep them safe and reassure them that everything was okay," says tenant Cherie McCallum.

"We were able to put them (tenants) up in a local hotel, look after their basic needs. So, shelter, food, any personal products they may need. Look after needs for the children that were involved in the event," says Dave O'Brien, Emergency Management Coordinator.

Investigators returned to the scene Tuesday morning.

The cause of the fire has not been identified, but it is not believed to be suspicious.