Black smoke rose above the Sistine Chapel on Tuesday, signaling that 115 Roman Catholic cardinals failed to agree on a new pope during the first day of the papal conclave.
The "princes of the church" have been deliberating inside the Vatican since swearing an oath of secrecy and entering the papal conclave at about 11 a.m.
The smoke was created by the burning of ballot papers used by the cardinals in their deciding vote, with chemical cartridges being added to ensure the smoke did not appear to be white - the sign that a decision has been reached.
The move follows the abdication of Pope Benedict XVI on Feb. 28.
It means the conclave will reconvene on Wednesday morning.
Rome (CNN) -- The work to choose a successor to retired Benedict XVI begins in earnest Tuesday, as the cardinals charged with the task prepare to be locked away in a secret election, or conclave, in Vatican City.
One of their number will almost certainly emerge from the process as the new spiritual leader of the world's 1.2 billion Roman Catholics.
Just a few hours after moving into Santa Marta, their residence at the Vatican for the duration of the process, the 115 cardinals who will choose the new pope took part in a morning Mass at St. Peter's Basilica.
They processed into St. Peter's, clad in scarlet robes, for a service in which they prayed for guidance in making a choice that could be crucial to the future direction of a church rocked by scandal in recent years.
n the afternoon, the 115 cardinal-electors -- those younger than 80 who are eligible to vote -- will go to the Pauline Chapel for further prayers.
They will then walk to the Sistine Chapel, chanting prayers as they go, to begin the secret election called the conclave.
The doors will be locked behind them, and after that the only clue the world will have of what is happening inside will be periodic puffs of smoke from a copper chimney installed in the chapel over the weekend.
Black smoke, no pope. White smoke, success.