A woman and two men in their twenties were arrested Saturday after an apparent bomb hoax on a TTC bus parked outside York University.

Toronto police said thousands of people had to be evacuated from the school after passengers on the bus found a paper bag on the floor with the words "I am a bomb" written on it.

Police say a commuter picked up the bag, thinking three passengers who had gotten off the bus at the York University stop mistakenly left it behind. The driver immediately called police.

An area of about 300 meters around the bus was evacuated for about an hour as emergency crews investigated the bag and determined it was not a bomb.

The school's food court had to be evacuated as did hundreds of parents who were at York for Parents Day at the university.

Police say during the closure a woman approached investigators and admitted to leaving the bag on the bus. Two other men were also identified as suspects.