Bishop Daily and about 150 antiabortion Catholics descended on the Ambulatory Surgery Center in Sunset Park Saturday to protest through prayer the center's abortions.

The demonstrators were countered by about 25 abortion-rights advocates and pro-choice Lt. Gov. Betsy McCaughey Ross, who appeared at their invitation.

The night before, a sniper killed Dr. Barnett Slepian in the kitchen of his suburban Buffalo home as he was talking with his wife and 15-year-old son. Slepian performed abortions as part of his women's health practice.

The upstate murder "made us more determined and angrier," said Nancy Millar, chairwoman of the reproductive rights committee of the National Organization for Women, who was at the Sunset Park clinic Saturday. "It [also] made it a bit more scary."

Every day the members of the group Helpers of God's Precious Infants, led by Monsignor Phillip Reilly, place "sidewalk counselors" outside the Surgery Center to try and talk to patients, offer them pamphlets, and dissuade them with graphic photos of what they say are aborted fetuses.

The group's attorney, Kathleen O'Connell, said a prayer vigil like the one held Saturday is organized once or twice a year by Bishop Daily. Diocese spokesman Frank DeRosa said the vigils are organized by Helpers of God's Precious Infants. DeRosa directed questions to Reilly, who did not return three calls.

The antiabortion demonstrators marched from St. Michael's Church . . . to . . . where they stopped in front of the Ambulatory Surgery Center for an hour of prayer.

About 25 members of the National Organization for Women chanted and held signs, one of which read, "Keep Your Rosaries off My Ovaries."

"I didn't know that the bishop was demonstrating until I saw the officer was putting up 'No Parking' signs," said the Ambulatory Surgery Center's administrator. . . .

The center, which has brought a lawsuit against Helpers that has been unsuccessful, has complained that the police department does not enforce clinic access laws and allows sidewalk protesters to harass patients.

The police department has said that local precincts are responsible for creating their own arrangements for enforcement of the access law. The 72nd Precinct's stationing of one officer during the center's hours of operations is sufficient, the department has said.

Additional officers were assigned last Saturday.

In recent days, Helpers have begun taking pictures of the staff at the center, [the administrator] said. In the past they had limited themselves to taking pictures and videotapes of the patients, he said.

"[A nun] came within two feet of me and took my picture with a flash camera," said [the administrator]. On Tuesday, someone was taking pictures from a car parked beneath the Gowanus Expressway on Third Avenue, [the administrator] said.

O'Connell said she had no knowledge of any picture taking but pointed out that that Helpers have had their pictures taken by security cameras at the center for the four years.

While Helpers have never been associated with violence, the heightened awareness of violence in the wake of the Buffalo murder raised concern over the picture taking. Radical groups have listed names and addresses and physical descriptions of doctors who perform abortions on Web sites. The operators of one such Web site put a line through the name of the Buffalo doctor within hours of his murder.

Asked about concern over personal safety because of the picture taking, O'Connell responded: "They would love to associate Helpers with violence and they've been unsuccessful. We don't operate a Web site and we're not in the business of harassing anybody."

[The administrator] said he was less concerned about the pictures than the patients. Outside of the drama and headlines of the murder of Dr. Slepian is the aggressive resistance they run into when they try to enter the center.

"The women in this borough are harassed daily in their attempt to access reproductive services," [the administrator] said. "The patients are the focus here and it's all about access. The drama around the story is unimportant."