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The surviving suspect in the Boston Marathon bombings has been moved from a civilian hospital to a Bureau of Prisons facility, a spokesman for the U.S. Marshals Service tells Fox News.

Dzhokhar Tsarnaev has been transported from the Beth Israel Deaconess Medical Center to the Federal Medical Center at Fort Devens in Ft. Devens, Mass., U.S. Marshals Service spokesman Drew Wade said.

The FMC Devens is a federal prisons facility for male inmates who require specialized or long-term medical or mental health care, according to the facility's website.

The move comes a day after New York City Mayor Michael Bloomberg revealed the suspects had Times Square in their sights before law enforcement authorities put an end to their bloody terror spree.

"New York was next on their list of targets," Bloomberg said of Dzhokhar and his brother Tamerlan.“The fact is, New York City remains a prime target for those who hate America and want to kill Americans.”

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Police Commissioner Ray Kelly said the brothers, Muslims from Dagestan, a breakaway republic in Russia, hatched their plot to attack Times Square while driving the streets of Cambridge last Thursday in a Mercedes SUV they had carjacked from a man who later escaped.

Kelly called the New York plot "spontaneous," and said they had six bombs with them in the car, some of which they hurled at police cars hours later when they were being pursued in a chase that culminated in Tamerlan Tsarnaev's death.

One of the bombs the brothers had in the stolen car was a pressure cooker bomb, identical to one used in the marathon attack, and packed with gunpowder and shrapnel, Kelly said. Both Kelly and Bloomberg noted surveillance cameras, a contentious subject in New York, played a key role in solving the bombing in Boston, Bloomberg's hometown. Still, the mayor said there was no way of knowing if the brothers could have pulled off a second attack in America's largest city.

"We don’t know if we would have been able to stop the terrorists had they arrived here from Boston," Bloomberg said. He said he did not know of a specific target within Times Square.

Times Square was targeted by Muslim terrorist Faisal Shahzad in a failed 2010 plot. Kelly said at least one Tsarnaev brother was photographed in Times Square last year, first on April 18 and then later on an unspecified day in November.

Kelly said the plot was revealed in a bedside interrogation of Dzhokhar Tsarnaev while he was in the hospital earlier this week. Kelly said Tsarnaev told investigators during his first interrogation that they were headed to New York City to "party." Subsequent questioning, however, revealed that the two brothers decided spontaneously that they would travel to Manhattan to detonate their remaining explosives, Kelly said.

The 19-year-old suspect spoke to FBI agents intermittently over a 16-hour period before a federal judge showed up at the hospital and read him his Miranda rights, after which he clammed up, according to law enforcement sources. But another senior law enforcement official, speaking to FoxNews.com, characterized the brothers' plans to go to New York as "aspirational, at best."

"I wouldn't say 'plot,' it was just talk," the source said.

The brothers are suspected of setting two bombs at the finish line of the race April 15. Three people were killed and more than 200 injured. Dzhokhar Tsarnaev could face the death penalty if convicted in the attacks, which he said were prompted by the brothers' religious beliefs and anger over the U.S. wars in Iraq and Afghanistan.

Fox News' Cristina Corbin and Pamela Browne contributed to this report.