Turnout was much higher than the organisers expected

Pope John Paul II has received a rapturous welcome from hundreds of thousands of young people during a visit to Spain.

At a rally outside Madrid he told the young Catholics they must be "artisans of peace", and work against a "spiral of violence, terrorism and war".

He also warned of the dangers of "excessive nationalism" - an apparent reference to the Basque separatist movement with its history of violence in Spain.

The Pope, on his first foreign tour for nine months, will on Sunday proclaim five new Spanish saints.

The 600,000 young people who turned out for Saturday's rally was twice as many as organisers had predicted.

Conquer enmity with the force of forgiveness Pope John Paul II In pictures: Pope's visit

The crowd listened to peace songs and religious music for more than eight hours as they waited for the pontiff to arrive. When he arrived in the early evening, he received a pop star's welcome, with cheering and flag-waving.

Seated on a white throne, the Pope spoke to the crowd in Spanish, in a firm voice despite his frail health.

The Pope, opposed to the war in Iraq, told the crowd: "Your response to blind violence and inhuman hate should be the fascinating power of love," he said.

"Conquer enmity with the force of forgiveness."

Spanish saints

The BBC's David Willey , travelling with the Pope, said the pontiff, who turns 83 this month, seemed invigorated by the presence of so many enthusiastic young people.

The Vatican says 94% percent of Spaniards are Catholics, but our correspondent says church-going in Spain is on the decline, as in other traditionally Catholic countries of Europe.

Before attending the rally, the Pope met Spanish Prime Minister Jose Maria Aznar, but a papal spokesman said they did not discuss Mr Aznar's support for the Iraq war.

Earlier on Saturday the Pope was welcomed at the airport by King Juan Carlos and Queen Sofia, and cheered by hundreds of ordinary Spaniards.

The Pope used a lift to descend from the plane, and a trolley to move along a red carpet laid out for him.

This is the Pope's fifth visit to Spain since he became the Pope in 1978. It is his 99th foreign trip.

Up to a million people are expected to attend Sunday's open-air mass in Madrid, where two priests and three nuns are to be canonised.

One priest, Pedro Poveda, was murdered in 1936 during the opening days of the Spanish Civil War.

The church says 4,184 clergy were killed during the war by the government side, which accused the church of backing General Franco.