Highway 401 has reopened but a stretch of southbound Yonge Street remains shut down in North York after a communications tower caught fire.

Toronto police said the fire was reported just before 9 a.m. and they subsequently closed down roads in the area due to the possibility that the tower might collapse on the highway or road.

The southbound lanes of Yonge Street are currently closed, but the northbound lanes reopened shortly after 4 p.m.

The OPP shut down the westbound collector lanes of Highway 401 from Leslie Street, as well as the westbound on-ramp at Yonge for much of the day. All lanes of the highway reopened at around 3:40 p.m.

It is not yet clear how the fire started.

Toronto Fire said the fire has been extinguished and that an engineer is on scene to assess the damage.

A crane has also been brought in to stabilize the tower, police said.

Drivers are being advised to avoid the area.