Black smoke poured out of the Sistine Chapel chimney on Wednesday, signaling that no pope had been elected as 133 cardinals opened the secretive, centuries-old ritual to choose a new leader of the Catholic Church.

The conclave to elect a new pope has officially begun, with a Vatican official calling out ''extra omnes'' and the door to the Sistine Chapel shutting.

The conclave to select the next pope has begun after Catholic cardinals from across the world filed into the Sistine Chapel Wednesday before sealing themselves inside.