An apparent security breach at Toronto's Pearson International Airport kept some flights on the ground late Wednesday.

All departing international flights from Terminal 1 were suspended while police searched for a male passenger who breached airport security.

The man had reportedly slipped through security without being checked at about 10:45 p.m. ET Wednesday evening.

Peel Region police Const. Lillian Fitzpatrick told Toronto radio station Newstalk 1010 they have a photograph of the passenger and continue searching for him.

Passengers who arrived at the country's busiest airport were kept on board aircraft while police conducted their search.

Pearson Airport has posted a tweet stating all operations were moving as scheduled although passengers were warned to expect some residual delays.