Service is currently suspended between Jane and Ossington stations on Line 2 due to an injury on the tracks.
Toronto police say there is an ongoing investigation at track level at Dundas West subway station, adding there is no risk to public safety at this time.
The TTC says shuttle buses will operate between the affected stations.
Riders can also use GO transit at Bloor or Union GO stations using a TTC fare.
No details on when service might resume have been released.