Last night, on the eve of President Barack Obama's national security speech, law enforcement officials arrested four Muslim men, at least three of whom are U.S. citizens, for conspiring to attack two Jewish synagogues in the Bronx and an Air National Guard installation in Newburgh, New York.

According to The New York Times:

The men, all of whom live in Newburgh, about 60 miles north of New York City, were arrested around 9 p.m. after planting what they believed to be bombs in cars outside the Riverdale Temple and the nearby Riverdale Jewish Center, officials said. But the men did not know the bombs, obtained with the help of an informant for the Federal Bureau of Investigation, were fake.

The arrests capped what officials described as a “painstaking investigation” that began in June 2008 involving an F.B.I. agent who had been told by a federal informant of the men’s desire to attack targets in America. As part of the plot, the men intended to fire Stinger missiles at military aircraft at the base, which is at Stewart International Airport, officials said.

The arrests came just before President Obama's speech today reiterating his determination to close down the prison complex at Guantanamo Bay, Cuba, and detain some prisoners inside the United States.

The New York Daily News says the president's critics may sieze on last night's arrests to argue that terrorism continues to be a clear and present danger to the United States and that detaining Guantanamo prisoners here is foolhardy.

Although the New York suspects were of the homegrown variety, the case may amplify anxieties about bringing Gitmo inmates here.

FBI Director Robert Mueller told Congress that they could radicalize other prisoners if moved to U.S. lockups or get back into the terror business if set free.

For more on the violent threat to places of worship, see Associate Editor Laura Spadanuta's "House of Worship Security and Training" from the April 2008 issue of Security Management.

UPDATE: The four men arrested were petty criminals that all met each other in prison, according to New York City Police Commissioner Raymond W. Kelly,reports the Times. If indeed the four suspects were radicalized in prison, it would once again call into question whether prisons foster terrorism and what U.S. prisons should do to curtail the phenomenon.

♦ Photo by DVIDSHUB/Flickr