Updated at 3:20 p.m. ET
The suspects in deadly bombing at the Boston Marathon also planned to attack Times Square in New York, authorities announced Thursday.
"The surviving attacker revealed that New York City was next on their list of targets," New York Mayor Michael Bloomberg said during an afternoon news conference. "He told the FBI, apparently, that he and his brother had intended to drive to New York and designate additional explosives in Times Square."
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 launch an attack with their five pipe bombs and a pressure-cooker bomb like the ones that blew up at the marathon.
Kelly said that the city was notified by the FBI's Joint Terrorism Task Force Wednesday night about the intentions of Tsarnaev and his older brother Tamerlan Tsarnaev.
Dzhokhar Tsarnaev traveled to New York at least once last fall. There is a photo of the suspect in Times Square.
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.
"We don't know if we would have been able to stop the terrorists had they arrived here from Boston," Bloomberg said. "We're just thankful that we didn't have to find out that answer."
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.
Kelly, citing interrogations carried out by the task force investigating the Boston Marathon attack, said that days after the bombing, the Tsarnaev brothers "planned to travel to Manhattan to detonate their remaining explosives in Times Square."
"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 26-year-old Tamerlan dead.
CBS News senior correspondent John Miller reported on "CBS This Morning" Tuesday that, according to investigators, the carjacking victim speaks little to no English, but authorities pressed him to remember recognizable words from his exchange with the bombing suspects.
The suspects openly boasted to the victim in English about their role in last week's bombing and carried out the rest of their exchange in Russian, Miller reported.
Miller reported that the victim said, "The only word I recognized was Manhattan," a word which "tripped a lot" of alarm for authorities, who quickly halted Amtrak service from Boston to New York and searched the trains.
The tip prompted the New York Police Department to "flip on its network of license plate readers at all bridges and tunnels coming into the city," Miller said. "They loaded all the license plates associated with these guys" to prevent possible entry into Manhattan.
On Wednesday, Kelly told reporters that he was told Dzhokhar Tsarnaev may have been intending to come to New York to party, or for a party, sometime after the bombings.
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