Three men accused of plotting to bomb New York synagogues and fire missiles at aircraft have appeared in court on weapons and conspiracy charges.
They and another man were detained after planting what they allegedly thought were bombs at two synagogues.
The three, wearing shackles, were detained until 5 June for a preliminary hearing, Judge Lisa Smith ordered.
Prosecutor Eric Snyder described them as "extremely violent men" and "eager to bring death to Jews".
James Cromitie (also known as Abdul Rahman), David Williams (aka Daoud and DL), and Onta Williams (aka Hamza) appeared in court in White Plains, New York.
Mr Snyder said Mr Cromitie had "complained" that the "best target" - the World Trade Center destroyed on September 11, 2001 - had already been targeted.
The fourth man, Laguerre Payen (aka Amin and Almondo), was due in court later.
Mr Payen's lawyer said he had been injured during his arrest and was receiving hospital treatment, according to AFP news agency.
Before the court hearing, New York Police Commissioner Raymond Kelly, visiting one of the synagogues, said all four "wanted to commit jihad".
FBI's allegations in full
(Source: New York Times)
[386 KB] Most computers will open this document automatically, but you may need Adobe Reader Download the reader here
New York terror sting detailed The men had allegedly agreed to buy explosives from FBI agents posing as Islamic militants.
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.
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.
Speaking outside the Riverdale Temple, one of the intended targets, New York City Mayor Michael Bloomberg praised the work of New York's police and the FBI.
The four have all made anti-Semitic statements, the police chief says The alleged plot served as a reminder to New Yorkers to remain vigilant "at all times", the mayor said.
"The bottom line is that we have to be constantly vigilant and we have to constantly be sure that we have the best police department in the world, that they are well led and well trained."
Mr Kelly, the police commissioner, stressed that the arrests were the result of a lengthy operation and that despite the serious nature of the charges, no-one was ever actually put at risk.
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.
<a class="bodl" href="http://news.bbc.co.uk/1/hi/world/americas/8061772.stm#map">See a map of alleged targets In their efforts to obtain weapons for the attack, the men dealt with an informant from the FBI, who is said to have provided the group "with an inactive missile and inert explosives."
"This was a very tightly-controlled operation but these individuals did place bombs - or what they thought were bombs - right in front of the building in which we are standing and the temple a few blocks away," Mr Kelly said.
Outlining the charges on Wednesday night, law enforcement officials said the group set up what they believed to be 30lbs (14kg) of explosives.
According to prosecutors, Mr Cromitie told an FBI informant in June 2008 that he was angry over the US-led war in Afghanistan.
The suspects allegedly wanted to attack National Guard planes 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".