LONDON, ONT. -- Police are warning residents to always have doors and windows of their homes locked following a number of suspicious fires in vacant or unoccupied buildings.

“The increase in reported suspicious fires recently is certainly a concern for us,” says Detective Sgt. Ryan Million.

“We have a number of active investigations on the go, and while we don’t have any information to suggest that they are linked, we can report that a number of them involved vacant buildings or unoccupied residences at the time of the fire. We continue to remind members of the public to report all suspicious activity to police,” adds Million.

The increase in fires has also caused concern for the London Fire Department.

“We encourage all residents to be fire safe and with many unknown safety concerns to not make entry into vacant buildings. As per the Ontario Fire Code, all vacant buildings are required to be secured against unauthorized entry," says Deputy Fire Chief Matt Hepditch.

Londoners can report issues with vacant buildings to the London Fire Department by calling 519-661-4565.

Residents should also check out their properties periodically or advise landlords if you won't be occupying the residence or  will be away for a period of time.