C-Train service has resumed along Seventh Avenue in downtown Calgary after a building fire forced officials to block off traffic for a few hours on Thursday morning.

Firefighters were called to a blaze at a two-storey building on Seventh Avenue between Centre Street and First Street southwest at about 6:30 a.m. MT just as the morning commute was getting underway.

Crews had the fire under control by 8 a.m. MT, fire officials said. Its cause is under investigation.

Calgary Transit operated shuttle buses while C-Train service was disrupted.

Customers were warned to expect some delays while normal service was restored.