New York - Four men suspected of planning to bomb a Jewish temple and shoot down military planes in upstate New York pleaded not guilty at their arraignment Wednesday.

The four suspects were arrested in May on suspicion of terrorist activities and for allegedly plotting to blow up a synagogue in the Bronx, a borough of New York City.

They were charged on eight counts, including conspiracy to use weapons of mass destruction, according to media reports.

The charges also said that James Cromitie, David Williams, Onta Williams and LaGuerre Payen tried to use anti-aircraft missiles to shoot down US military planes at the Air National Guard Base at Stewart Airport in Newburgh, New York.

The men were arraigned at a federal court in White Plains, New York.

The four were arrested as they left a vehicle allegedly loaded with explosives, which turned out to be inert and sold to them by undercover FBI agents.

In May, US authorities said the men were given fake explosives in a year-long sting operation conducted by the FBI using an informant. They also received a disarmed anti-aircraft missile.

"The bombs had been made by the FBI technicians. They were totally inert. No one was ever at risk," New York Police Commissioner Raymond Kelly said after the arrest on May 21.

The four could face life in prison if convicted.(dpa)