Subway service has been restored and Hydro crews are assessing damage after an electrical vault fire in an underground parking garage in midtown Toronto temporarily shut down service along parts of the University-Spadina line this afternoon.

Subway service was suspended for about an hour and a half between St. Clair West and Union stations due to a loss of power, according to tweets from the TTC.

A Toronto Hydro official confirmed the power outage was due to a problem with underground equipment at St. Clair Avenue West and Bathurst Street.

Six buildings — including three TTC-owned buildings as well as the Clairhurst medical centre — also briefly lost power.

The cause of the fire has not yet been confirmed, but Toronto Hydro said it's common at this time of year for salt mixed with snow to get into the underground vaults.

Hydro crews are assessing the damage, which will take some time to fix, the utility said.

Toronto Fire Services Capt. Mike Strapko told CBC News the fire blew a door off the garage. There was also extensive smoke at the scene.