Authorities are investigating whether the explosion at the Times Square military recruiting office was connected to strikingly similar bombings at the British Consulate in 2005 and the Mexican Consulate in 2007, both in New York, but ruled out a link to mysterious letters sent to Capitol Hill offices. Investigators are currently scrutinizing surveillance video and forensic evidence at the site.

A small explosion was set off at a U.S. military recruiting center in New York Times Square early Thursday. No injuries were reported, but the explosion made a hole in the front door of the recruiting center. For more than two hours, New York City police officers and firefighters cordoned the area.

Apparently an improvised device was detonated at the Armed Forces Recruiting Center on the traffic island located on the 43rd and 44th Streets, Seventh Avenue and Broadway just before 4 a.m. By 6:45 a.m. traffic around Times Square was permitted and the subway service was restored after a temporary interruption. The explosives were packed in a metal ammunition box, authorities said.

There are several similarities with the attacks on the two consulates: all three took place within a 30-minute span, around 3:30 a.m., were apparently carried out by whom appears to be a man on a bicycle with a hooded jacket or sweatshirt hiding his face. The bicycle used in this case was apparently found and is currently being examined for clues.

The explosive used in all three attacks is a low-grade or low-velocity explosive, raising the possibility that the person or group is involved with some kind of activism rather than terrorism. The recruiting station which was the target of the attack has witnessed regular antiwar protests since the start of the Iraq war in 2003. Even so, until today it hasn’t been attacked.

It was reopened in September 1999 after it was redesigned by Stephen Cassell and Adam Yarinsky of the Architectural Research Office for $1 million. Inside you can find space for Army, Navy, Air force and Marine recruiters and a bathroom.