BANSKA BYSTRICA, Slovakia -- He was clearly suffering -- unable to walk and speaking with difficulty -- but Pope John Paul II rallied enough to greet thousands of faithful Friday and pay tribute to victims of the "dark days" of communism.

Battling his ailments, the pope pushed ahead with his Slovak pilgrimage, looking more alert than on his arrival 24 hours earlier. The 83-year-old pope, who is struggling with Parkinson's disease and crippling hip and knee ailments, presided over a two-hour Mass for pilgrims braving a chilly drizzle in the central city of Banska Bystrica.

Speaking in Slovak in a sometimes slurred voice, the pontiff thanked God that "he allowed me another apostolic trip in the name of Christ." But after beginning his homily by greeting the crowd, which chanted, "Let the Holy Father live!," John Paul asked Cardinal Jozef Tomko to read most of the rest before finishing the last few lines himself.

Although the pope's visit got off to a rough start Thursday, when he failed to get through his arrival remarks for the first time in 102 foreign trips, papal spokesman Joaquin Navarro-Valls said the trip "absolutely" would continue.

The Polish-born pope's fierce anti-communism stance is credited with helping to end communist rule across Eastern Europe. His visit will end Sunday, when the pope will beatify as martyrs a bishop and a nun who were jailed and tortured in the 1950s.