Four men who allegedly plotted to blow up a New York synagogue and shoot military planes at an upstate New York Air National Guard base were arrested tonight by the FBI on charges including plotting to use weapons of mass destruction within the United States.
The men -- at least three of whom appear to be radicalized recent converts to Islam, according to law enforcement sources -- allegedly planned to detonate car bombs constructed with the powerful plastic explosives in front of a synagogue in the Riverdale section of the Bronx, and were arrested tonight as they allegedly thought they were carrying out their plot.
The arrest came following an FBI sting operation in which the men allegedly believed they had purchased a working Stinger missile and live C-4 plastic explosives.
The missiles and explosives they purchased in the sting were dummies, according to court documents and law enforcement officials.
Rep. Peter King, R-N.Y., the ranking Republican on the House Homeland Security Committee, who was briefed on the bust earlier this week, told ABC News Radio the suspects were arrested tonight outside the temple and community center they hoped to bomb, with the inert explosives.
"They purchased the C-4 from the FBI, they purchased the stinger missile from the FBI and they were there tonight with the car bombs outside the temple and the community center," King said.
"If the FBI were not involved, this would have been an absolute tragedy," he said. "This was a real plot, they were in the act of carrying it out tonight."
New York City Police Chief Ray Kelly said no one was ever at risk, because the devices they allegedly believed were lethal had been supplied by the FBI.
According to a statement from the U.S. Attorney's Office of the Southern District of New York, the four men arrested were identified as James Cromitie, David Williams, Onta Williams and Laguerre Payen, all of Newburgh, N.Y.
"The defendants planned to strike military planes with surface-to-air guided missiles and to destroy a synagogue and a Jewish community center with C-4 plastic explosives," Acting U.S. Attorney Lev Dassin said in a statement released today. "Thanks to the extraordinary, collaborative work of our law enforcement partners, the defendants' plans were thwarted and the defendants are under arrest."
In addition to the charge of conspiracy to use weapons of mass destruction within the United States, which carries a maximum sentence of life in prison, the four are also charged with conspiracy to acquire and use anti-aircraft missiles, which carries a maximum penalty of life in prison with a minimum sentence of 25 years.
The investigation of the men began in June 2008, according to court documents, when Cromitie met with a person who had been an FBI informant for more than six years and allegedly talked about his anger about U.S. forces in Afghanistan, and said he was interested in doing "something to America."
In a recorded meeting between Cromitie and the informant on Dec. 5, 2008, according to the documents, the suspect allegedly asked the informant to get him surface-to-air missiles and explosives.
On May 6, according to the documents, Cromitie, David Williams and Payen drove with the informant from Newburgh to Stamford, Conn., where the three defendants were shown what they were told were a missile system and improvised explosive devices containing C-4 plastic explosives.
After inspecting the supposed weapons, they allegedly brought them back to Newburgh and put them in a storage locker, according to the documents.
"The three defendants celebrated their achievement shouting 'Allah Akbar,' an Arabic phrase which means, 'praise be to God,'" according to the documents.
ABC News' Dean Schabner contributed to this report.