Investigators are combing over surveillance footage after a low-level explosive went off early Monday morning outside a Starbucks on the Upper East Side.

The blast went off around 3:30 a.m. at the corner of 92nd Street and 3rd Avenue.

No one was injured.

The explosive took out windows at a Starbucks on the corner, forcing several people in the apartments above to be evacuated.

"We're going to analyze the type of explosive that's been used. As I say, it's been described by our bomb experts as a low explosive," said Police Commissioner Ray Kelly.

Kelly said investigators are looking into any similarities between Sunday's explosion and others that have taken place in the city over the last four years including one at the British consulate in May 2005, another at the Mexican consulate in October 2007, and at the Times Square military recruiting station in March 2008.

"It's unnerving to come down and see the police commissioner holding a press conference across the street from your home, it shakes you up a little bit," said Jay Hecht, an Upper East Side resident.

"My concern, of course, is who did it and why? Or was it just mischievous activity by some teens, we don't know at this point," said Judith Berman, an Upper East Side resident.

Kelly says police will be checking surveillance cameras to get more information. He also says there were no notes, or advance calls about the blast.

As for the device itself, Kelly would not rule out that it may have involved some sort of fireworks or at least the powder used in fireworks.

He also noted that Starbucks shops have been targeted in other cities, and that investigators would be looking into this as well.

Anyone with information about the case is being asked to contact Crime Stoppers by calling 1-800-577-TIPS, by texting TIP577 to CRIMES, or by going to NYPDCrimeStoppers.com.