"It was unbelievable. I am proud of being American but I couldn't believe my eyes something like this could happen," said Tabbaa

Donna Lieberman, executive director of the New York Civil Liberties Union which is helping represent the plaintiffs, condemned what she described as the "over-zealous and counter-productive ethnic and religious profiling" encouraged by government security policies in the wake of the September 11 attacks.

"They are engaging in profiling," said Lieberman, adding that "the government detained people because they attended a conference that was perfectly legal, exercising their basic rights."

None of the citizens who were detained had done anything unlawful, nor were they charged with any unlawful act," Lieberman told reporters.

"You don't lose your rights when you're a Muslim. You don't lose your rights when you cross a border, and you certainly don't lose your rights by attending a religious conference," she added.

One of the plaintiffs, Sawsaan Tabbaa, an orthodontist from Buffalo in New York, said the experience at the border crossing "was the most humiliating I have ever gone through."

"It was unbelievable. I am proud of being American but I couldn't believe my eyes something like this could happen."

Tabbaa said she had refused to be digitally fingerprinted on the grounds that she had done nothing wrong, but was physically forced into compliance.

"I started sobbing like a kid," she said.

At the time of the incident, numerous press reports quoted Customs and Border Protection (CBP) spokeswoman Kristie Clemens as claiming the government had "credible information" that Islamic conferences were being used to promote and fund terrorist activities.

On Wednesday, Clemens said she was unable to comment on a specific case that was the subject of a lawsuit, but added that the "priority mission" of the CBP was to "prevent terrorists” and their weapons entering the country.

"As we continue to pursue this mission, we will continue to work with all communities to protect the freedoms of all Americans," she said.

Islamic leaders vehemently deny the charges.

Tabbaa's son, Hassan Shibley, 18, said the border guards had initially insisted they were picked "at random ", but when he entered the processing room he saw that all the occupants were Muslim.

"It was like I was walking into my local mosque," Shibley said.

Lieberman, whose organization filed the suit along with the American Civil Liberties Union and Council on American-Islamic Relations, said there was nothing about the RIS conference to raise suspicions.

"If the government has suspicions about criminal activities they have every right and indeed the obligation to go after those suspicions," Lieberman said.

"This is a case of rounding up the usual suspects in derogation of their rights and in derogation of all of our liberties."

A recent nation-wide poll, conducted by the Cornell University, showed that at least 44 percent of the Americans backs curbing Muslims’ civil rights and monitoring their places of worship.