BRNO, Czech Republic - More than 120,000 people packed a field in the Czech city of Brno on Sunday to hear Pope Benedict XVI call for a spiritual renewal in the former communist nation.

The pope is one a three day visit to the Czech Republic, which is about to mark the 20th anniversary of the Velvet Revolution that ended communist rule and which he has used to hail the end of what he called "oppressive regimes".

People from across Eastern Europe came for the giant mass where Benedict again attacked the communist past, saying: "History has demonstrated the absurdities to which man descends when he excludes God from the horizon of his choices and actions.

"Here, as elsewhere, many people suffered in past centuries for remaining faithful to the Gospel, and they did not lose hope," he added.

Religious belief was suppressed by the Communist regime, which labelled the Church the people's enemy, put priests under secret police surveillance and banned the Catholic press and Catholic associations.

Benedict told the huge crowd gathered autum sun in a field near Brno-Turany airport that the technical and social change of the modern world could also be a threat to faith.

"Your country, like other nations, is experiencing cultural conditions that often present a radical challenge to faith and therefore also to hope," he told the mass.

Faith and hope "have been relegated to the private and other-worldly sphere, while in day-to-day public life confidence in scientific and economic progress has been affirmed," he noted.

The 82-year-old pontiff warned: "We all know that this progress is ambiguous: it opens up possibilities for good as well as evil."

"Technical developments and the improvement of social structures are important and certainly necessary, but they are not enough to guarantee the moral welfare of society."

One of the goals on the pope's trip is to restore faith in the largely secular country. In his prayer, Benedict called on those present "to remain faithful to your Christian vocation and to the Gospel, so as to build together a future of solidarity and peace."

But the fall of communism has failed to bring a religious revival in the Czech Republic: less than a third of the country's 10.38 million people are Catholic, according to the Vatican.

Some pilgrims spent the night in tents at the field to get a good spot for the mass.

Youngsters in traditional costumes mingled with robed priests and families with prams, warming their hands on mugs of tea or nibbling on cake and biscuits in the morning chill.

The arrival of Benedict in his distinctive white Popemobile drew cries from the crowd, who waved small white-and-gold Vatican flags and large Czech, Slovak, Austrian and Polish banners.

Out of the 120,000 people present, some 10,000 had come from abroad. One bishop came from Bangladesh, according to the Brno diocese organisers.

Former Slovak president Michal Kovac who attended the mass, told AFP: "Meeting the Pope is always a big thing for me... the world today must, now more than ever, honour Christian values."

Benedict's first visit to the Czech Republic began on Saturday in Prague, where he visited the Our Lady of Victory Church and met former president Vaclav Havel, hero of the 1989 coup who became president after spending years in Communist prisons.

The Pope hailed the fall of communism in eastern Europe 20 years ago, giving thanks for the region's "liberation from those oppressive regimes."

After the two-hour mass in Brno on Sunday, Benedict was to return to Prague to attend an ecumenical meeting and meet scientists.

His visit will symbolically end with a mass for an estimated 35,000 people in Stara Boleslav near Prague on Monday, which is the feast of St Wenceslas, the Czech martyr and patron saint who was murdered in the town on September 28, 935.