Is this another FBI sting operation
Four men were arrested late on Wednesday over alleged plots to attack targets in and near New York.
The four planned to blow up synagogues and use Stinger missiles to bring down military planes, US prosecutors said.
The men were seized after allegedly planting what they thought were bombs near two synagogues in the Bronx area.
They earlier agreed to buy explosives from FBI agents posing as Islamic militants. New York has been on alert for a new terror attack since 9/11.
The four are charged with conspiracy to use weapons of mass destruction within the US and conspiracy to acquire and use anti-aircraft missiles, officials said.
The charges carry jail terms of between 25 years and life imprisonment. The four, all Muslims, are to appear in a federal court later.
They were named as James Cromitie (also known as Abdul Rahman), David Williams (aka Daoud and DL), Onta Williams (aka Hamza) and Laguerre Payen (aka Amin and Almondo)
A senior FBI official in New York said three were US citizens and one was from Haiti.
BBC defence and security correspondent Rob Watson says the case appears to be a classic sting operation against suspected home-grown militants rather than a plot with any links to known international terrorism.
New York Mayor Michael Bloomberg said the alleged plot showed "homeland security threats against New York City [were] sadly all too real". 'Sought weapons'
The arrests were the result of a year-long investigation, officials said.
"The defendants wanted to engage in terrorist attacks," said Lev Dassin, acting US attorney for the Southern District of New York.
"They selected targets and sought the weapons necessary to carry out their plans."
According to prosecutors, the men planned to detonate cars packed with C-4 plastic explosives outside the Riverdale Temple and the Riverdale Jewish Center in the Bronx district of the city.
They also intended to target military planes at the New York Air National Guard base at Stewart Airport, 60 miles (85 km) north of New York City.
In their efforts to obtain weapons for the attack, the men dealt with an informant from the FBI, who provided the group "with an inactive missile and inert explosives."
"They had bags that were set up that they believed to be bombs, carrying about 30 pounds of explosives which they believed to be explosives," FBI official Joseph Demarest told reporters. 'Afghan war anger'
According to prosecutors, Mr Cromitie - whose parents are from Afghanistan - told an FBI informant in June 2008 that he was angry over the US-led war in Afghanistan.
He "expressed an interest in 'doing something to America"'.
From October 2008, the informant began meeting him regularly along with the four others at a house in which the FBI had concealed video and audio equipment.
The group allegedly "expressed desire" to attack targets in New York and Mr Cromitie "asked the informant to supply surface-to-air guided missiles and explosives", prosecutors say.
In April 2009, the group agreed on the synagogues they intended to attack and proceeded to conduct surveillance, including taking photographs of the warplanes at the military base, prosecutors say.
Mr Cromitie allegedly pointed out Jews in the street, saying "if he had a gun, he would shoot each one in the head", according to the district attorney's statement.
According to the statement, he told the informant that attacking the Jewish community centre would be a "piece of cake".
He also said he would be interested in joining Jaish-e-Mohammed - a Pakistan-based group considered a terrorist organisation by Washington - "to do jihad". http://news.bbc.co.uk/2/hi/americas/8060684.stm