No trains are running between Kipling and Jane stations on Friday, the TTC says. (Evan Mitsui/CBC)

There is no subway service on the western-most stretch of Line 2 Friday, and the TTC says the closure could last several days as crews work to repair communications cables damaged by a fire.

No trains are running between Kipling, Islington, Royal York, Old Mill and Jane stations, the transit agency says.

Between 40 and 60 shuttle buses will be operating along Bloor Street in their stead but significant delays are expected throughout the day. Commuters can use a TTC fare to take GO's Lakeshore West line to downtown.

Eastbound subway service from Jane Station is unaffected, the TTC said in a statement.

A fire broke out along a track-level fence at Islington Station around 3:30 p.m. Thursday, according to TTC spokesperson Stuart Green, and eventually spread to adjacent subway infrastructure.

The fire severely damaged a signalling box and a number of cables that enable communication between trains, Green said. TTC crews are still working alongside police and firefighters to determine how the blaze started, he added.

Green was unable to say when regular service might resume on that length of Line 2.

"We don't have a timeline on that just yet. It could be a few days," he told CBC Toronto.

No one was injured in the blaze, Toronto Fire said.