After another round of voting, the Roman Catholic Church's cardinal electors have failed to agree on a new pope.
Black smoke billowed out of the Sistine Chapel chimney, signaling that no candidate had yet reached the required two-thirds majority of at least 77 votes.
After a first inconclusive vote on March 12, the 115 eligible cardinals spent the night at a Vatican guesthouse.
White smoke will announce a new pope, to replace Benedict XVI, who retired last month.
A total of four rounds of voting are expected to be held on March 13.
Front-runners to lead the world's 1.2 billion Roman Catholics include Italy's Angelo Scola and Brazilian Odilo Scherer.
The cardinals are completely isolated from the outside world.
The Vatican has taken precautions, including electronic jamming devices, to prevent any leaks.
Based on reporting by dpa and Reuters