Pope Francis has sparked concerns about his health after unexpectedly pulling out of a key Easter ceremony at the last minute on Friday, reigniting worries about the 87-year-old pontiff's increasingly frail condition.

The Vatican announced that the pope withdrew from the Way of the Cross ceremony to "preserve his health" ahead of other events scheduled for the holiest weekend in the Christian calendar. His armchair, which had been set out on the hill facing the Colosseum in Rome for the ceremony, was swiftly removed just moments before the scheduled start.

In a statement, the Vatican explained that "to preserve his health ahead of tomorrow's vigil and the Easter Sunday mass," Pope Francis would follow the Way of the Cross from his residence, the Santa Marta Residence, where he lives.

Although the pope had missed last year's ceremony due to bronchitis, this year's decision came as a surprise. However, a Vatican source told AFP that there was "no particular concern" about his health on Friday and that the decision to withdraw was "simply a measure of caution."

Despite his recent health issues, Pope Francis has maintained a packed agenda in the week leading up to Easter. He presided over a Good Friday mass in St Peter's Basilica at the Vatican and washed the feet of 12 women at a prison in Rome on Thursday as part of another Easter rite.

On Sunday, he is scheduled to preside over the Easter mass in St Peter's Square before giving the "Urbi et Orbi" blessing.

Pope Francis, who became pope in 2013, has faced various health challenges in recent years, including knee and hip pain that now requires him to use a wheelchair regularly. However, he has previously indicated that he would only consider resigning in the event of a "serious physical impediment."

Despite the unexpected withdrawal from Friday's ceremony, thousands of people had gathered, with the Vatican estimating the crowd at around 25,000. For the first time during his papacy, Pope Francis himself wrote the texts read out at each of the 14 Stations of the Cross, symbolizing Christ's journey from death sentence to crucifixion.