A suspect has been arrested after a firefighter was assaulted while battling an encampment fire in Rosedale Saturday morning.

Crews were initially called to Sherbourne Street and Rosedale Valley Road shortly before 10:30 a.m. for reports of a fire under a bridge.

"In the course of fighting that fire, one of our firefighters was assaulted by someone who was on the scene," Toronto Fire Chief Matthew Pegg said.

The firefighter was taken to the hospital with injuries initially considered as serious but non-life-threatening, according to Toronto paramedics. Pegg said the firefighter's condition improved and was later released from hospital and has returned to active duty.

The circumstances surrounding the incident are unknown at this time.

"He and his crew were actively fighting this fire. And as you hear me talk about all the time, they pay particular attention, first and foremost, to making sure that everyone is safe. So they're focused on that. And I don't know exactly what happened. It just ended up in a situation where he was assaulted by someone, and the police intervened," the fire chief said.

Meanwhile, police said officers searched the area and were able to locate and take the suspect into custody.

"As always, I'm deeply appreciative for all that Toronto police do. They were there with us. They were able to quickly bring that under control and deal with that situation," Pegg said.