Toronto police are looking for four men on bicycles who are alleged to have assaulted a man in a North York park and then taken his dog.

Police said they received a call about the stolen dog, "Charlie," a white female Shih Tzu, in Derrydowns Park, in the Finch Avenue West and Tobermory Drive area, at about 3 p.m. on Monday.

Police say a man was walking his dog when he was approached by four men, all riding bicycles. They say one of the men punched the dog owner, another put a knife to his throat, then the group took the dog and fled.

Officers who were called to the scene were unable to find the suspects or the dog, described as weighing 10 to 15 pounds.

Police said all four suspects are black, aged 20 to 25 years, and all were riding black mountain bikes.

One has a medium build, was unshaven and was wearing a red baseball hat with no logo and a red windbreaker-style jacket. He punched the man.

The second suspect has a medium build and was wearing a navy-blue jacket.

The third suspect was wearing a black hooded sweater, a red Canada Goose vest and black pants. He was carrying the knife.

The fourth suspect was wearing a light-coloured sweater.

Anyone with information is asked to contact police at 416-808-3100, Crime Stoppers anonymously at 416-222-TIPS (8477).