Pope Francis on Sunday celebrated Easter Mass with tens of thousands of Catholics at Saint Peter's Square in Vatican City before his traditional blessing, as concerns persist over his health.

The 87-year-old arrived in a wheelchair to preside over the Mass from 10 a.m. (0800 GMT) in cloudy and windy weather, with the events broadcast live around the globe.

Francis will pronounce the "Urbi et Orbi" (To the City and the World) blessing at midday where he is expected to bring up the international conflicts raging worldwide.

The Ukrainian government has responded angrily and vowed never to surrender after Pope Francis said the country should have “the courage to raise the white flag” and negotiate an end to the war with Russia.

“Our flag is a yellow and blue one. This is the flag by which we live, die, and prevail. We shall never raise any other flags,” Ukraine’s foreign minister, Dmytro Kuleba, said on social media on Sunday.

Pope Francis has decided to punish one of his highest-ranking critics, Cardinal Raymond Burke, by revoking his right to a subsidized Vatican apartment and salary in the second such radical action against a conservative American prelate this month, according to two people briefed on the measures.

Pope Francis is evicting US Cardinal Raymond Burke, an outspoken critic, from his Vatican apartment and revoking his salary.

Cardinal Burke is part of a group of American conservatives who have long opposed the Pope's plans for reforming the Catholic Church.

A Vatican source told the BBC that Pope Francis has not yet carried out his intention to evict the 75-year-old.

And the decision is not meant as a personal punishment, the source added.

Pope Francis has stripped one of his top American critics, Cardinal Raymond Burke, of his Vatican housing and salary privileges, the Associated Press is reporting.

According to the AP report, which is based on conversations with two anonymous sources briefed on the measures, the pope discussed his planned actions against the American prelate at a Nov. 20 meeting of Vatican office heads.

The pope reportedly said that Burke was a source of “disunity” in the Church and that he was using the privileges afforded to retired cardinals against the Church.

The Vatican has confirmed a ban on Catholics becoming Freemasons, a centuries-old secretive society that the Catholic Church has long viewed with hostility and has an estimated global membership of up to six million.

"Active membership in Freemasonry by a member of the faithful is prohibited, because of the irreconcilability between Catholic doctrine and Freemasonry," the Vatican's doctrinal office said in a letter published by Vatican media on Wednesday.