BOSTON (AP) — The Boston Marathon bombing suspects had planned to blow up their remaining explosives in New York's Times Square, New York officials said Thursday.

Police Commissioner Raymond Kelly said Dzhokhar Tsarnaev told interrogators from his hospital bed that he and his older brother had decided spontaneously Thursday night to drive to New York and detonate their remaining explosives — a pressure-cooker bomb like the ones that blew up at the marathon, plus five pipe bombs.

The plan fell apart after the Tsarnaev brothers were intercepted by police in a stolen car and got into a fierce gun battle that left Tamerlan Tsarnaev dead, Kelly said.

Dzhokhar, 19, is charged with carrying out the Boston Marathon bombing that killed three people and wounded more than 260, and he could get the death penalty.

He was interrogated in his hospital room over a period of 16 hours without being read his constitutional rights. He immediately stopped talking after a magistrate judge and a representative from the U.S. Attorney's office entered the room and gave him his Miranda warning, according to a U.S. law enforcement official and others briefed on the interrogation.

The Tsarnaev brothers "planned to travel to Manhattan to detonate their remaining explosives in Times Square," Kelly said, citing the task force that has been investigating the Boston Marathon attack.

"They discussed this while driving around in a Mercedes SUV that they hijacked after they shot and killed the officer at MIT," the police commissioner said. "That plan, however, fell apart when they realized that the vehicle they hijacked was low on gas and ordered the driver to stop at a nearby gas station."

The driver escaped and called police, Kelly said. That set off the gunbattle and manhunt that ended a day later with Dzhokhar captured and his brother dead.