A suspicious package that led New York Police to close off Times Square turned out to be an abandoned lunch box.

A failed attempt to detonate a car bomb in Times Square on Saturday has heightened security in the most populous US city.

Police cordoned off several blocks of Seventh Avenue for about 90 minutes while a bomb squad member wearing a protective suit examined the white lunch box that contained a water bottle and found nothing dangerous.

The cooler was found by a police officer on patrol in the pedestrian mall at West 46th Street and Broadway, New York Police Department spokesman Paul Browne said.

Prosecutors on Tuesday charged Faisal Shahzad, 30, a naturalized US citizen born in Pakistan, with attempting to use a weapon of mass destruction and trying to kill and maim people in the United States.

Shahzad is accused of driving a crude homemade bomb of gasoline, propane gas, fireworks and fertilizer into crowded Times Square on Saturday evening.

New York Police Commissioner Ray Kelly said the Times Square plot was the 11th thwarted attack on New York City since hijacked airliners destroyed the World Trade Center's twin towers on Sept. 11, 2001, killing more than 2,700 people.