CAMDEN, N.J. - Six Muslim men suspected of plotting to massacre U.S. soldiers at Fort Dix were ordered held without bail Friday.

Prosecutors argued that the men, all born outside the United States, pose a flight risk. They are being held at a federal detention center in Philadelphia.

The men were arrested Monday during what the FBI said was an attempt to buy AK-47 machine guns, M-16s and other weapons. They targeted Fort Dix, a post 25 miles east of Philadelphia that is used primarily to train reservists, partly because one of them had delivered pizzas there and was familiar with the base, according to court filings. Their objective was to kill “as many American soldiers as possible,” the documents said.

The men have lived in and around Philadelphia for years, worshipped at moderate mosques and worked blue-collar jobs. Four are ethnic Albanians from the former Yugoslavia, one is from Jordan and one is from Turkey.

As they were led into the courtroom, each of the suspects smiled to relatives and friends, many of whom wept and blew kisses to them. Only one of the men, Mohamad Ibrahim Shnewer, 22, asked to be released on bail, and friends and relatives offered to post properties they owned as collateral.

Assistant U.S. Attorney Stephen Stigall argued against letting Shnewer be released to the custody of his parents while awaiting trial. He said many of the illegal actions that the government alleges Shnewer committed happened or were planned at his parents' house.

Defense lawyers for some of the men said they are considering attacking the prosecution's reliance on two paid informants who infiltrated the group more than a year ago and recorded conversations with the defendants.

Authorities said they first learned about the men in January 2006 after a tip from a clerk at a Mount Laurel electronics store.

Circuit City spokeswoman Jackie Foreman said Friday that credit for the tip is shared by two employees. She declined to name them but said the company has “communicated its appreciation.” She declined to give details. The pair called police because a home video the men wanted transferred to a DVD looked like it might have terrorist links, U.S. Attorney Christopher J. Christie said.

Five of the men - Shnewer; Serdar Tatar, 23; Dritan “Anthony” or “Tony” Duka, 28; Shain Duka, 26; and Eljvir “Elvis” Duka, 23 - are charged with conspiring to kill uniformed military personnel, an offense punishable by life in prison.

Agron Abdullahu, 24, is charged with helping illegal immigrants obtain weapons. He could face 10 years in prison if convicted.

Abdullahu, who faces the least serious charges of the six, will have another bail hearing next Thursday.