Pope John Paul II led thousands of Roman Catholics in an open-air mass in Saint Peter's square to celebrate Palm Sunday. The pope appeared to be in good form at the start of Holy Week and just one month before he celebrates his 84th birthday.

Tens of thousands of pilgrims joined Pope John Paul in Saint Peter's square in a colorful mass, which opened Holy Week at the Vatican. They waved palm fronds and olive branches, in remembrance of Jesus's entry into Jerusalem a week before his death.

Security was particularly tight, but discreet. Police checked the people flowing into the square and said no one complained because they understood that security is in everyone's interest. Uniformed and plainclothes officers moved among the crowd.

During the more than two-hour long Palm Sunday ceremony, the pope's words were addressed mainly to young people.

The pope said that it is certainly difficult to understand the message of the cross in our time, when material well-being and comfort are being proposed as priority values.

He urged young people not to fear proclaiming the gospel of the Cross. The pope told them not to fear going against the current. Young people cheered enthusiastically.

The 83-year-old pope, resplendent in red vestments, appeared in good spirits and spoke in a relatively strong voice. As often happens with the pontiff before large gatherings with crowds, he again appeared to have found renewed energy.

The Palm Sunday mass opened the most important week in the Christian calendar. The pope will also be celebrating masses on Holy Thursday, lead the Way of the Cross on Good Friday and celebrate Easter mass on Sunday, giving his message and blessing to the world.