A low-order explosive device was thrown at the recruitment center in New York's Times Square early today, authorities said on Thursday.

Surveillance footage from private security cameras released by NYPD shows a bicyclist getting off a 10-speed bike at 3:40 am Times Square military recruiting station where a small bomb was detonated. The blast occurs three minutes after the man arrives and is followed by a brief flash and a cloud of white smoke.

In a second briefing today, police Commissioner Raymond Kelly said the device was unsophisticated and was placed in a small ammunition box like ones readily available in Army-Navy stores.

But this type of explosive can certainly cause injury or death,'' Kelly said.

The blast did little damage, but was significant enough to blow out the windows and doors of the recruiting center and to rattle a nearby hotel. Police say they later found the bike in the trash.

New York City Mayor Michael Bloomberg condemned the perpetrators and said such actions would not affect life in the city.

Whoever the coward is that committed this disgraceful act on our city will be found and prosecuted to the full extent of the law, Bloomberg said at the same briefing.

We will not tolerate such attacks, nor will we let them destroy our freedom to live peacefully and safely in the greatest city in the world.

Commissioner Kelly said one witness at the scene saw a man riding a bicycle in a suspicious manner just before the explosion. The man was wearing a hood and dark colored clothing and had a backpack. The witness did not see the man's face, nor did the witness see the man throw anything.

Subway service has been restored after a disruption that started at 4:24 a.m. and lasted about an hour and 15 minutes, according to the New York City Transit Authority.

Police have asked if anyone has any information on the blast or who did it is asked to call the city's Crime Stoppers tip line 1-800-577-TIPS.