VATICAN CITY - Vatican officials announced Monday the pope is resigning at the end of the month.

According to the Vatican, Pope Benedict XVI , 85, plans to step down Feb. 28.

Bloomberg and Reuters reported the 265th pope is stepping down due to his advanced age.

"I have come to the certainty that my strengths, due to an advanced age, are no longer suited to an adequate exercise of the Petrine ministry," the pope said in a statement on the Vatican radio website.

The Associated Press is reporting the pope's brother says a doctor told the pope not to take transatlantic trips for health reasons.

Pope Benedict was elected to office April 19, 2005 and was inaugurated on April 24, 2005.

Last year the pope started using a cane on occasions and recently he appeared to have trouble reading the text of an address he delivered in Rome, according to The Daily Telegraph.

The resignation sets the stage for the Vatican to hold a conclave to elect a new pope by mid-March, since the traditional mourning time that would follow the death of a pope does not need to be observed.

There are several papal contenders in the wings, but no obvious front-runner as was the case when Benedict was elected pontiff in 2005 after the death of Pope John Paul II.

The Cathedral Basilica of the Immaculate Conception in Denver is holding mass at 7 a.m., 12:10 p.m. and 5:30 p.m. on Monday.

The pope's last tweet from @Pontifex was posted just about 24 hours ago, and read: "We must trust in the mighty power of God’s mercy. We are all sinners, but His grace transforms us and makes us new."