Police surrounded the Hell’s Angels clubhouse on 3rd Street yesterday with a hostage negotiation van, a detail from the emergency services unit, an armored truck, and snipers stationed on rooftops across the street.

But a confrontation was averted when police acquired a search warrant yesterday afternoon and entered the building without incident.

The search was part of an investigation into an injured woman who police said may have been assaulted by members of the motorcycle gang late Sunday night. By last night, one member of the group, whom police did not identify, was in custody but had not been charged with a crime.

An anonymous 911 call at 11:40 p.m. Sunday led officers to the woman, who was lying in front of a New York Law School dormitory at 81 E. 3rd St., near the entrance to the clubhouse, at 77 E. 3rd St. Police did not identify the woman, who was described as Caucasian and in her 40s.

The woman was suffering from head injuries and was unable to speak when officers found her, police said. Paramedics rushed her to Bellevue Hospital, where she underwent surgery yesterday. A hospital spokeswoman said she was in serious but stable condition last night.

Police sources said witnesses told investigators that at about 11:30 p.m., they saw several members of the Hell’s Angels carry the woman out of the clubhouse and leave her on the sidewalk.

“I saw the lady unconscious. She had a lump on her eye” and was bleeding “out of her mouth,” a teenager who lives at 3rd Street and the Bowery, Chris Guzman, 18, said. “Me and some other guy called the cops.”

At about 7 a.m. yesterday, detectives arrived in front of the clubhouse and cordoned off the block with police tape for most of the day. Several members of the Hell’s Angels were not allowed to drive their cars away because detectives said the street was a “crime scene,” a lawyer for the gang, Ronald Kuby, said.

“For most of the day and evening, they’ve turned a chunk of the Lower East Side into Fallujah,” he said.

The three-story building has a clubhouse on the ground floor with a bar, a pool table, and furniture, Mr. Kuby said. Some members of the Hell’s Angels live in apartments on the other floors.

One man in front of the clubhouse yesterday who identified himself as a member of the gang refused to comment on the case. “We don’t know what’s going on, either,” he said.

Residents of the East 3rd Street block said that though their stretch of the East Village is usually safe and quiet, the clubhouse has been more active than usual lately.

“This past week, there has been more and more noise coming from the Hell’s Angels building,” a man who lives at 80 3rd St. said. One day last week, he was woken up at 5 a.m. by an argument between a man and woman in front of the building, the man, who requested anonymity because he feared retaliation from the gang, said.

“For the city, a renegade motorcycle gang is always a problem,” a man who grew up on First Avenue and 3rd Street, Fran Westal, 39, said.