New York police commissioner Dermot Shea has hailed officers who shot dead a man on the steps of a New York City cathedral after he shouted "kill me!" and started firing two semi-automatic pistols, Reuters, CNN and others reported Monday.

The suspect was yelling "kill me," according to witnesses, Shea said. He said the motive for the shooting wasn't clear.

The shooting occurred at the end of a Christmas choral concert late Sunday at the Cathedral Church of St. John the Divine. The gunfire sent people leaving the church running for cover.

Three police officers on the scene fired 15 rounds - with at least one striking the gunman in the head and killing him, Shea told reporters. No bystanders were injured in the crossfire, officers said.

The man, who was not identified, was taken to Mount Sinai Morningside hospital where he was pronounced dead. Police found a bag believed to belong to the suspect that contained a bible, duct tape, several bladed weapons, wire, rope and a full can of gasoline. "I think we can all surmise the ill motives of the contents of this bag," Shea said.

The officers ordered the gunman several times to drop his weapon before they shot him, a Reuters photographer who was on the scene, said. Choir members had already made their way inside the church by the time the shooting erupted, which lasted several minutes, the photographer said.

"It was just beautiful, and then at the end this man started shooting. Everybody's in shock," cathedral representative Lisa Schubert told The New York Times.

A Reuters photo shows the gunman wearing a black coat, white hat and a face covering printed with what looked like a Dominican Republic flag. The photo shows him holding a gun in each of his hands.