No date has been set for the conclave. The Vatican said Tuesday that it was waiting for five more cardinals to arrive before setting the date for the election.
Speculation is mounting that the conclave might begin around March 11 with the aim of having a new pope installed by March 17. That's the Sunday before Palm Sunday and the start of the holy week.
Officials said 107 of the 115 voting-age cardinals attended the first day of pre-conclave meetings on Monday. They took an oath to maintain rigorous secrecy to all matters related to the election.
On Tuesday, cardinals signed off on a telegram sent to Benedict XVI thanking him for his "brilliant" ministry and his "untiring work in the vineyard of the Lord." Benedict stepped down last Thursday, becoming the first pope to do so in 600 years.
The Associated Press contributed to this report.