NEW YORK (REUTERS) - Police arrested a man after he left a crude explosive device in a briefcase during rush hour at a busy New York City bus terminal, according to a criminal complaint filed on Thursday (March 16).

The device did not detonate.

Arsenio Mason, 39, is accused of leaving the briefcase on a chair inside a deli at the Port Authority of New York and New Jersey bus terminal on Wednesday evening.

The case contained what appeared to be a "flash bang grenade," as well as a knife, bolt cutters and screwdrivers, the Port Authority Police Department said.

Police arrested Mason after he returned to retrieve the bag. They say he was carrying methamphetamine, an illegal stimulant, in a pipe.

There has been a visible increase in police officers patrolling the bus terminal, one of the main entry points into Manhattan, in recent months in the wake of deadly attacks on civilians in European cities.

Mason, of Jersey City in New Jersey, is facing charges of possession of a weapon and possession of a controlled substance, according to a complaint provided by the Manhattan district attorney's office.

Mason's attorney did not immediately respond to a request for comment. A court set bail at US$750,000 (S$1 million) on Thursday.

Mason is due back in court on March 21.