LONDON, ONT. -- London fire crews were kept busy Sunday afternoon, dealing with a pair of separate blazes.

A vacant building at the corner of Adelaide and Nelson in London caught fire Sunday afternoon causing first responders to shut down the busy street.

Video supplied to CTV News shows the back of the house catching fire with what appears to be an small explosion.

Fire crews and police responded just after 1:30 p.m.  to find heavy smoke but were able to knock the fire down.

Police spent the afternoon interviewing witnesses and are looking for more people who may have left the area as a number of onlookers were taking video.

Meanwhile across town later in the afternoon, crews were called to a townhouse fire on Griffith Street.

A cooking fire started on the main floor of one of the townhouses and was quickly put out.

All residents were evacuated and two people were assessed by paramedics.

Damage is estimated to be over $100,000.