The 21-year-old attacker set upon a 45-year-old man last night at a Queens subway station exit, police said. The victim, who fended off his attacker with an umbrella, suffered cuts on his head. He was in stable condition at a hospital.

Later the attacker dropped the machete and fled inside a nearby two-story building, where he went to the roof and started smoking cigarettes before setting liquid-filled containers on fire and hurling them into the street, witnesses said.

He threw at least four explosive devices, one of which struck a livery cab and set it on fire, police said. However no one was injured.

As a precautionary measure Police evacuated nearby homes in the Richmond Hill neighborhood and sealed off the block during a one-hour standoff with the man. Officers swarmed the area on foot while a police helicopter hovered over the man.

Officer Robert Zajac said the ordeal ended when he told the man, "It's time to come down now," and the man complied.