In a tradition that scholars date to the 19th century, smoke released from a chimney will be colored white if the cardinals have made a decision, or black if they remain deadlocked.

At the end of each voting round, black smoke means a new pope has not yet to be selected, while white smoke indicates a new pope has been chosen.

Black smoke appeared from a chimney atop the Sistine Chapel at the Vatican on Thursday, signalling that cardinals meeting in a secret conclave did not elect a new pope during their two morning ballots.