ROME, JUNE 24 -- Austrian President Kurt Waldheim arrived here tonight for a controversial meeting with Pope John Paul II as police detained Nazi hunter Beate Klarsfeld and four U.S. Jewish activists who had planned to lead demonstrations protesting the meeting at the Vatican Thursday.

Klarsfeld and her four companions, one of whom was New York rabbi Avi Weiss who had led a demonstration on the steps of St. Peter's Basilica earlier today, were detained at Rome's Leonardo da Vinci airport as they prepared to protest Waldheim's arrival.

Several hundred activists from France, Belgium and Italy are expected to march from the Rome synagogue to the Vatican Thursday to protest the pope's decision to receive Waldheim, who has been accused of complicity in war crimes while serving with the German Army in World War II. Waldheim has denied the charges.

Klarsfeld and the four Americans were handed over to Italy's antiterrorist police for questioning. It was believed that they would be questioned about a smoke bomb that went off in Klarsfeld's hotel room. Several smokebombs and leaflets opposing the Waldheim visit were reportedly found in the room.

Waldheim, on his first official visit abroad since his election as president almost a year ago, made no statement on his arrival in Rome. He was greeted by Archbishop Eduardo Martinez Somalo, the Vatican's undersecretary of state.

The Austrian president, who is not making an official visit to Italy, was also met by an Italian Foreign Ministry protocol officer and left by car for the Rome hotel where he will stay.

Earlier in the day Weiss, of the Hebrew Institute in Riverdale, N.Y., and three other Jewish activists from New York staged a demonstration against Waldheim's audience with the pope on the steps of St. Peter's Basilica while wearing mock concentration camp uniforms with yellow Stars of David.

Protesting Waldheim's alleged Nazi past, Weiss and his companions urged the pope not to embrace the Austrian leader because his "hands were dripping with Jewish blood." The four-man protest, watched by about 100 tourists and almost as many journalists, came as international ire over the pope's meeting with Waldheim reached a crescendo.

Following outraged protests against the meeting from Israel and world Jewish leaders, demonstrators from Austria and elsewhere in Western Europe were reported to be on their way here tonight by train and bus to join Thursday's protest.

The protest, which organizers said would be much larger than today's, was planned for the hour the pope will meet with Waldheim.

"We are all very upset that at a time when virtually all democratic leaders of the West have shunned Waldheim because of his Nazi past, the pope has chosen to meet him," said Klarsfeld after watching Weiss' demonstration at St. Peter's this afternoon.