An ambulance and a group of Harvard University Police officers descended on the sixth semiannual Leverett House 80s Dance on Saturday night to stop what some students feared were the beginnings of a riot.

While more than 750 students danced to the songs of Wham! and the Bangles in the Leverett dining hall, hundreds more tried to push their way in, forcing the Harvard University Police Department (HUPD) detail officer on hand to call for backup.

Students and officers had different perceptions of the HUPD response to the situation.

While students said six or seven officers brandishing nightsticks tried to break up the crowd in the Leverett court-yard, an HUPD official said four or five officers responded to a routine call for backup.

According to Leverett House Committee Chair Russel G. Perkins '97, the episode began at around 11:15 p.m., after the number of students in the dining hall exceeded safe limits. Door attendants stopped the flow of students into the dining hall, permitting only one person in for each person who left.

"Once the line stopped flowing in, it started to back up," Perkins said. "They started to get a little rowdy and people started to push. People were getting squished. People slipped into their mob mentality."

When house tutors told the D.J. to stop the music for the purpose of crowd control, partygoers continued to sing "Celebration" by Kool and the Gang.

At 11:47, the HUPD watch officer on duty felt the crowd outside was getting too large and called for backup, accord- ing to Sgt. Robert J. Kotowski.

Police dismissed the episode as a routine action, but students on the scene said the officers took the incident seriously.

"They kind of came in thinking it was a riot, with their clubs up," Perkins said. "But no force was used at all."

Students said they were afraid those pushing in line and moshing might create a dangerous situation.

"I was just on line and there were about a couple hundred people behind me and one guy was thrown on top of the people and was carried over the crowd horizontally," said Alexis Z. Martin '98.

"I was right at the front of the line getting pushed up against chair," Martin said. "There were some big guys pushing. I jumped up on top of the chair so I wouldn't get hurt."

She said the detail officer commanded students to back off and get away from him.

"The cops were screaming. I saw one cop pull away a guy that was harassing the first cop," Martin said.

Leverett House Master John E. Dowling said he tried to make his way to the entrance but could not get to the door because of the crowd congestion.

"It was wall-to-wall people from the dining hall to the door," Dowling said. "It was a potentially dangerous situation. The popularity of the party brought more students than the officer could handle."

But Kotowski said that the incident was unremarkable and added that the crowd dispersed quickly after the extra officers arrived on the scene.

"The potential for a problem was diffused before anything actually happened," Kotowski said. "If it continued any further, there may have been the potential for students to be hurt."

An additional officer remained with the detail officer until the party ended at 1 a.m., Kotowski said.

"The extra officers helped to communicate to the crowd from back to the front," he said. "It wasn't a crowd that was unruly as much as uninformed."

One state trooper monitoring his radio responded to the incident, according to Kotowski. The state trooper parked his vehicle on Memorial Drive but did not enter the building after being told by HUPD that the situation was under control.

A few minutes before the detail officer called for back-up, the Leverett tutors on hand had called an ambulance for one student who was drunk, according to Dowling.

Emergency medical technicians were carrying the student on a stretcher as police arrived to quell the disturbance.

Dowling said there was no alcohol at the party and guessed the student had arrived drunk.

Despite the chaos, Dowling said HUPD reacted appropriately, and he termed the party a success.

"There was one student they were lifting over the crowd, but it was all in good fun," Dowling said. "I just wanted to tell people that they didn't need to push, we'd have another party next semester. Nobody was hurt. It all ended up fine."

And many students who were in the dining hall said in interviews that they were not even aware of what was happening outside.

"We might think of having the party somewhere bigger next semester," Perkins said