Gunfire tore through Harvard Square last night, frightening by standers and resulting in a collective effort by Harvard and Cambridge Police to determine suspects and motives. Apparently, no one was injured.

Eyewitnesses said the commotion began at about 8 p.m., when a number of young men stepped out of a maroon Volkswagen Jetta GL and mysteriously started shooting. Two young women were reported to be in the front seats.

Between four and eight shots were fired near the Pit, the suaken area behind the MBTA escalators between John F. Kennedy Street and Mass. Ave. People near the shooting either ran into the stores along the intersection or dove to the sidewalks to protect themselves, witnesses said.

"We heard eight gunshots ring out and we ran into Au Bon Pain to get away," said Christopher B. Stone '94, who was on his way to a restaurant with a friend at the time of the incident.

"It seemed to me to be coming from behind the subway station," he said.

"I got on the floor in the car," said Lucia A. Petrulh, a Somerville resident who was parked outside Out of Town News, waiting for a friend. "Everyone reading magazines at the newsstand was on the floor."

One bullet shattered a first floor window in the BayBank Harvard Trust building. Another landed in a mail box on Mass. Ave. in front of BayBank.

After the shooting, a number of youths ran off in different directions. Two ran through the Urban Outfitters store from the JFK Street entrance to the Brattle Street entrance, where police were reportedly waiting to apprehend them.

Others allegedly involved in the shooting scattered throughout the surrounding streets.

"I had my Walkman on and I heard something so loud I shut it off," said Terence P. Mann '96, who was standing outside of Au Bon Pain. "Then there were four guys who ran down Dunster and one guy chasing them."

"One guy ran in front of my car to CVS," Petrulli said.

Cambridge Police were on the scene almost immediately, Mann said.

"The cops were here by the time the last shooting happened. It was amazing," he said.

Himani Singh '95, another eyewitness, agreed that the police response was extraordinary.

Police, Police Cars Everywhere

"Almost immediately there were eight cop cars from every direction. There were regular cars and undercover cars with blue lights on top," she said. "Then there were these men with walkie-talkies wearing Red Sox jackets and things like that who were running around. And they all kept coming."

Some minutes after the police arrived on the scene, a maroon Jetta appeared at the intersection of Brattle and JFK Streets and was immediately attacked by some young men.

"There was a car with two girls in it and somehow this guy wound up kicking in the windows," said James Akula, a 17 year-old Cambridge resident who was standing in the Pit during the mayhem.

Harold Murphy, superintendent of the Cambridge Police Department, said he believed the car incident was "coincidental rather than planned."

"I think someone was pissed because they couldn't get through the Square. It's nothing new," he said.

Petrulli, however, said the cops searched both the young women and the car.

Detective Richard Estes of Harvard Police apprehended one suspect near the Apley Court complex on Plympton St., according to the police desk.

Other suspects were rounded up by the Cambridge Police, who were the first called to the scene.

The police have already accounted for two of the many bullets reportedly fired. One shattered the plate-glass window above the BayBank main entrance on Mass. Ave. Another was found in the mail-box on the side walk outside of BayBank.

Singh, who was in BayBank when the shooting began, said she was so terrified by the experience that it seemed unreal.

"The people in BayBank asked me if it was all for that movie," she said, alluding to the recent filming of the film "With Honors" on the Harvard campus.

"It was just a shocking thing," said Stone.

Officials at the Cambridge Police station said late last night they were unable to comment on the shooting.

Vikram A. Kumar and Rajath Shourie contributed to the reporting of this story.