Pope warns against 'false gods'

Tens of thousands of young pilgrims, many waving national flags and wearing orange floppy hats made for the August 16-21 World Youth Day celebrations, cheered his arrival at Madrid's Almudena Cathedral.

Wearing a white cassock, scarlet cape and white skullcap, and with a gold pectoral cross hanging from his neck, the 84-year-old pontiff descended from the popemobile.

The leader of the world's 1.2 billion Roman Catholics sprinkled holy water at the entrance and donned a white, gold-embroidered mitre before walking down the aisle of the 19th century cathedral to celebrate mass for 6,000 young people preparing to join the priesthood.

"Do not be intimidated by surroundings that would exclude God and in which power, wealth and pleasure are frequently the main criteria ruling people's lives," the pope warned the seminarians.

"You may be shunned along with others who propose higher goals or who unmask the false gods before whom many now bow down."

The pope drew a thunderous applause as he announced he will bestow an extremely rare honour on a Spanish saint, Saint John of Avila, by proclaiming him a doctor of the Church.

Only 33 doctors of the Church -- reserved for figures of eminent doctrine and remarkable holiness -- have been proclaimed since 1295, and the last was in 1997.

Earlier in the morning, the pope heard confession from four young pilgrims -- two women and two men -- in one of 200 temporary confessionals set up in Madrid's city-centre Retiro park.

He will hold a prayer vigil in the evening at an airbase southwest of the capital, where the pilgrims will spend the night under the stars on an esplanade the size of 48 football pitches.

Hundreds of thousands of pilgrims have poured into the Cuatro Vientos base's grounds, which resembled a massive rock festival.

The faithful sprawled across the ground with backpacks, sleeping bags, many waving national flags. They propped up beach parasols and umbrellas to try to fend off the punishing August sun.

The pope celebrates mass there on Sunday morning at a white altar almost 200 metres (660 feet) long in front of a vast wave-shaped stage and under a giant parasol "tree", made of interwoven golden rods.

The sheer scale of the celebrations in Madrid has sparked angry demonstrations, however, over the expense at a time of economic hardship, with unemployment for under-25s running at more than 45 percent.

Thousands of protesters marched in central Madrid late Friday to protest the expense and to decry police crackdowns on earlier demonstrations.

"This is not the pope youth!" and "No to police violence!", the crowd chanted, waving their hands in the air.

Scores of police prevented the activists from marching into the city's central Puerta del Sol square, where clashes took place on both Wednesday and Thursday nights.

Baton-wielding anti-riot police in Madrid late Thursday dispersed about 150 protesters from the square. On Wednesday 11 people were reported lightly injured when police broke up a protest.

Protesters -- including some priests -- are fuming over the official €50.5 million price tag, excluding the cost of police and security, of the Catholic youth celebrations.

But organisers of the festivities say most of the cost will be covered by a registration fee from the pilgrims, and the celebration will be a massive tourist boost for Spain.