Priests shelter themselves from the rain underneath umbrellas as they leave after a prayer vigil at the Cuatro Vientos aerodrome in Madrid
Priests shelter themselves from the rain underneath umbrellas as they leave after a prayer vigil at the Cuatro Vientos aerodrome as part of World Youth Day festivities in Madrid, August 20, 2011. Reuters

A torrential rainstorm forced Pope Benedict to abandon a speech to hundreds of thousands of young people gathered at an aerodrome outside Madrid on Saturday.

Driving rain and wind forced the organisers of the event to recommend Benedict halt his address after delivering just a few opening words of welcome.

A massive storm got up and officials halted the programme as it was impossible for the pope to continue battling against the elements, a witness said.

But people were surprisingly calm and stayed where they were, with many welcoming the break in the weather after baking in the afternoon heat ... Besides there was nowhere to run for shelter in this huge open arena.

In a text of the speech released in advance on Saturday, Benedict had written that marriage must be between a man and a woman and called for the respect for life, in apparent criticism of Spain's legalisation of gay marriage and abortion.

In Madrid's city center, gay activists staged a protest to defend same sex partnerships, the latest in a series of demonstrations against the visit.

The pope's speech had been intended for young people gathered outside the Spanish capital for an all-night prayer vigil that will culminate on Sunday with the end of the Catholic Church's World Day of Youth.

Before the storm hundreds of pilgrims had been treated for dizzy spells because of 40-degree heat.

On the third day of a visit which has been marked by protests, some of them violent, the pope had called in his prepared speech for respect for God's gift of life during.

He quoted from the Bible definition of marriage in which a man and a woman become one flesh and also urged his listeners to be open to the gift of life within marriage.

Spain's legalisation of abortion on demand last year and gay marriage in 2005 have stoked tensions between Spain's Socialist goverment and the once overwhelming powerful Roman Catholic Church in the country.

At a mass on Saturday morning he told some 4,500 seminarians that priests must lead saintly lives and only enter the priesthood if they were convinced they could live by all the church's rules, including celibacy.

The church has been mired in scandal in recent years over disclosures that priests sexually abused children in many countries and that church officials covered up the abuse.

The cost of the pope's trip to Madrid has angered some Spaniards struggling with recession and high unemployment. Heavy security has surrounded the pontiff, with roads cut off to traffic and thousands of police on the streets.

Benedict's trip has reignited criticism by Los Indignados (The Indignant), a group whose mainly young members occupied Madrid's Puerta del Sol square in May to protest against high unemployment and government spending cuts.