OTTAWA (Reuters) - Erin O'Toole, the leader of Canada's main opposition Conservative Party, conceded defeat on Tuesday after failing to block Prime Minister Justin Trudeau's Liberals from securing a third term.

       Speaking to supporters in his home electoral district outside Toronto, O'Toole said he had called Trudeau to congratulate him. TV networks predicted the Liberals won a minority government.

       As of 12:40 a.m. (0440 GMT), the Conservatives were leading or elected in 121 of 338 seats, while the Liberals were on 157.

       (Reporting by Julie Gordon in Ottawa; Editing by Peter Cooney and Tom Hogue)