Amid concern for the pope's safety while in Poland, John Paul II is traveling under tight security here that inhibits the spontaneous contact he had with fellow Poles during his 1979 pilgrimage.

The pope's isolation, inside a protective cocoon termed the "zero zone," is frustrating for many who have flocked for a glimpse of him. Chanting, "Come closer," hundreds of thousands of Polish youths massed last night below the high stone walls of Jasna Gora monastery were able to draw John Paul II down the steps of his elevated altar. But he remained well removed from the enthusiastic crowd.

A ranking member of the Polish episcopate spoke of the additional strain on the pope of having to reach out to his countrymen across a cordon of security precautions. "Anything is more difficult if you have to perform it in a cage," the official said. "Security measures are terrible now."

Mixed with the frustration of having their pontiff fenced off is an element of understanding for the necessity of protecting a world leader who has had two attacks on his life in the past two years.

"Perhaps it's for the best," shrugged one middle-aged woman, referring to the blue-uniformed militia squads evident wherever the pope goes. "This way the pope will see what we here have been up against these past months."

In contrast to the heavy guard around the pope, Polish police are not intervening against the overwhelming displays of pro-Solidarity sentiment that have marked all of the immense papal gatherings, drawing a warning by a government spokesman today.

An agreement between Polish and Roman Catholic officials makes church marshals responsible for keeping order in the crowds, while primarily confining police units to the perimeters, manning traffic barricades and controlling access to and from the papal sites.

City and church officials share policing responsibilities along papal motorcade routes. This has led to the incongruous sight of groups of long-robed priests standing side by side with uniformed militiamen sporting rubber clubs.

"This visit will take place in a completely different political atmosphere than the previous one," said Col. Bronislaw Galant, the militia commandant in Czestochowa, shortly before the papal visit began. "A serious relaxation of public discipline has taken place. Religious emotions can easily intermingle with political ones."

Despite what authorities said was an understanding that church marshals would prevent open-air masses from turning into political demonstrations, there has been little effort to rip down Solidarity banners or muffle other shows of antistate sentiment. But the pope has shown a finely tuned ability to raise or lower the pitch of his audiences as he pleases.

Much of the Poles' fear for the safety of the pope stems from a deep distrust of Soviet intentions and from concern for the machinations of some Polish circles opposed to the relatively pro-church policy being pursued by Gen. Wojciech Jaruzelski. The Warsaw government knows that if anything were to happen to the pope here, it could trigger an uprising.

Unlike the run-up to major political demonstrations in the past year, Polish authorities refrained from detaining known Solidarity activists before the pope's arrival. But as if to underscore their security concerns, they announced several weeks ago the arrest of a man for allegedly planning to blow up the altar at St. Anna's Mountain, where the pope will be Tuesday, with a bomb activated by sunlight.