Four men accused of plotting to blow up synagogues and shoot down military planes believed that the scheme concocted in a government sting would kill innocent New Yorkers, a prosecutor said Monday in closing arguments at the men's trial.

Lawyers for James Cromitie, Onta Williams, David Williams, and Laguerre Payen accused the government of entrapping harmless dupes with a paid FBI informant posing as a representative of a Pakistani terrorist group.

"The FBI did exactly what it's supposed to do," Assistant U.S. Attorney David Raskin told a jury in federal court in Manhattan.. "It caught four dangerous men before they could do any real harm. ... Ordinary people wouldn't even dream of what these defendants did."

Prosecutors said the men also wanted to shoot down U.S. military planes at an Air National Guard Base in Newburgh, N.Y.

The four suspects have pleaded guilty of conspiracy to use weapons of mass destruction and conspiracy to acquire and use anti-aircraft missiles to kill U.S. officers and employees.

Three of the suspects are U.S. citizens and all four are converts to Islam.

The men were arrested by FBI agents in 2009 after they planted the devices in the Riverdale section of the Bronx while under heavy surveillance. All of the devices were fakes supplied by the FBI.

The closing arguments were expected to continue Tuesday. The case could go to the jury later this week.