SOFIA, Bulgaria — He is wheeled around in a cart, sits slumped in his chair looking exhausted and reads only small portions of his speeches, heavily slurring his words.

A four-day visit to Bulgaria has put Pope John Paul II's deteriorating physical condition in full view, alarming his hosts. But aides say he intends to continue his travels, feeling encouraged by outpourings of affection.

The 82-year-old pope on Saturday made a pilgrimage to one of Bulgaria's holiest sites, visiting a 1,000-year-old monastery in an effort to end a millennium of distrust between Catholics and Orthodox Christians.

It remains one of the unfulfilled goals of his 24-year papacy and one he intends to pursue.

He traveled by helicopter to the southern town of Rila for a visit to the Rila Monastery, not far from the tomb of St. Ivan Rilsky, patron saint of the Bulgarian people.

John Paul sat hunched over and one of his hands shook as he read just a few scattered lines of his remarks with badly slurred speech before letting an aide deliver the rest.

The visit, the pope's 96th foreign tour, has been a major test of his stamina. His speech is often slurred and his hands tremble — symptoms of Parkinson's disease — and he walks with difficulty because of knee and hip ailments. In Rila, it took him a minute to shuffle 50 feet to pay his respects at the tomb of the late King Boris III.

The Vatican has confirmed that the pope will travel in July to Canada, Mexico and Guatemala. He is to visit his native Poland in August. As if to end speculation that John Paul might decide to retire while in Poland and remain in his homeland, the Vatican said a stop in Croatia in September for a beatification is in preparation.

"The condition of the pope is visible to all," Vatican spokesman Joaquin Navarro-Valls told reporters Saturday. "He will continue to travel within these limitations. The pope notes the big show of affection wherever he goes, and this encourages him."

However, one of the Orthodox churchmen who welcomed John Paul expressed alarm at the pope's condition.

Metropolitan Simeon praised the pontiff's mission and goals but said: "I think people around him should tell him he has to stop. He is suffering like Christ."

In Rila, John Paul praised the monks' work as "a great gift for the whole church" and spoke of "the richness of Eastern monastic spirituality."

With his own church rocked by a sex abuse scandal, the pope spoke of the monks' daily struggle against temptations, speaking of the "evil suggestions that the demon tries to plant in their hearts."

"More than ever in the lives of Christians today, idols are seductive and temptations are unrelenting," he said.

Across Eastern Europe, and especially in Russia, embittered Orthodox leaders have made no secret of their resentment of Roman Catholic expansion into traditionally Orthodox countries like Bulgaria. Orthodox hard-liners consider Catholicism heresy, and many Catholics see the Orthodox faith as mystical and alien to the liturgy of Rome.

The pope met Saturday with Prime Minister Simeon Saxcoburggotski, Bulgaria's popular former king, who returned to his homeland last year after decades in exile in the West and became premier when his party swept parliamentary elections.

He then returned to Sofia, the capital, for meetings with the leader of Bulgaria's Muslim community and with local Protestants, and bless a statue in the Roman Catholic cathedral of Pope John XXIII, who served as a Vatican diplomat in Bulgaria early in his career.

The local Muslim leader, Grand Mufti Selim Mehmed, said Muslims were praying for the health of the pope, who held up during the long afternoon and seemed energized by his meetings and the welcome he was receiving.

In a moving moment for the fiercely anti-communist pontiff, an elderly priest who spent more than 20 years in gulags and prisons in Bulgaria embraced John Paul and thanked him for coming to the country. The two men stood together on the cart used to wheel around the pope.

As the pope was leaving a church in Sofia, Vatican security guards picked up toddlers who had been waiting with their parents outside and handed them up to the window of the bulletproof "popemobile" to receive a kiss from the pontiff.

There are only about 80,000 Catholics in the nation of 8 million; most live in or near the second-largest city of Plovdiv, where the pope will celebrate an open-air Mass on Sunday, the final day of his visit.