Police are investigating after a violent night in Midtown ended with four people being shot and more than 30 others arrested.

It happened late Sunday night when one man and three women were shot between 12:08 a.m. and 2:08 a.m.

A 21-year-old man was shot at 41st Street and Seventh Avenue, a 21-year-old woman was shot with a BB gun at 51st Street and Seventh Avenue, and two teenaged women were shot at 34th Street and Seventh Avenue.

All were taken to Manhattan hospitals and are expected to recover.

One officer also received a minor leg injury during the violence.

Police say a total of 33 people were arrested in connection with the incident. The charges range from disorderly conduct and resisting arrest to weapons possession.

However, no arrests have been made directly to the shootings.

Local business owners say they believe the shootings were the result of a gang initiation and have become an annual occurrence this time of year. McDonalds doubled it usual security guard presence in preparation.

Those who were in the area said it made for a frightening scene.

"It all started when I came in around 12 o'clock," said one resident. "The crowd was so much. From the west side all the way to the east side, you know."

"It was scary to come off the train and see all the running around by tourists, kids being subdued in handcuffs. It was just chaos out here," said another. "It was really, really crazy."

"Too many people. People fighting and stuff," said a local worker. "People looking for problems. It was pretty hectic so you had to keep your eyes open."

A police spokesman said at least some of the trouble may be caused by young people who leave the international auto show at the Javits Center and spread out in Midtown. The police spokesman didn't use the word "gangs," but the mayor did.

"The mayhem in Midtown appears to be a bunch of gang members wilding and it certainly has nothing to do with terrorism or anything else," said Mayor Michael Bloomberg. "A bunch of people who think it is cute to cause chaos. We have loaded area with police but they can't be everywhere."

The shootings prompted police to ask the Hilton Hotel to lock its entrance on 41st Street.