Pope John Paul II has begun a grueling four-day visit to Slovakia amid increasing concern about his health. But, even though he displayed a moment of weakness at the Bratislava airport, the pontiff is expected to hold several open air masses.

Pope John Paul traveled to Slovakia to urge the mainly Catholic nation to resist materialism as it prepares to join the European Union.

Shortly after his delayed arrival at Bratislava airport, the 83-year-old pontiff, who suffers from Parkinson's disease and hip and knee ailments, appeared short of breath as he began to read his speech, and his words got slurred. A local priest was called in to read a portion of his speech. Vatican observers said the cause of his weakness was travel fatigue.

"The pope is urging Slovaks to bring to the construction of Europe's new identity the contribution of their rich Christian tradition," he said. "Do not be satisfied with the sole quest for economic advantages."

This was an indirect reference to the debate within the European Union about a new constitution, which the Vatican says should include a reference to the continent's Christian heritage.

Church officials have also been concerned about a new abortion law in Slovakia, where seven out of 10 people are Catholics. In July, parliament enacted legislation to make abortion legal until the 24th week of pregnancy, instead of the current 12 weeks.

But Slovakia's president Rudolf Schuster, who held talks with the pope Thursday, has vetoed the measure, saying the issue should first be submitted to the courts. Mr. Schuster described the pope as a "high moral authority" who was bringing "a message of hope".

"It is with great happiness that he welcomes the pope on behalf of Slovakia," he said. "The pope is considered to be a moral guide and beloved by his nation."

The Vatican's chief organizer for papal visits, Renato Boccardo told Vatican Radio that the pope wants to send the message that it is important, especially for the former Communist countries to have a Christian tradition.

Mr. Boccardo says it is also one of the reasons why the pontiff will beatify a bishop and a nun who were imprisoned under decades of communist rule when Slovakia was still part of Czechoslovakia.

"Next Sunday the holy father will proclaim, beatify two persons, a bishop and a nun who are martyrs," he said. "And of course their example and willingness will be given to the youth and the actual generation."

More than 5,000 police have been assigned to provide security for what is the pope's 102nd trip abroad after authorities said they were investigating a death threat made against the church leader.