An Arab-American civil rights group filed a lawsuit Tuesday against the federal government in a bid to access information about the nationalities of more than 230 people arrested for immigration violations.

The suit, filed by the American-Arab Anti-Discrimination Committee, names the U.S. Department of Homeland Security and its Immigration and Customs Enforcement unit as defendants. It was filed under the Freedom of Information Act in U.S. District Court in the District of Columbia after two years of unsuccessful attempts to learn the nationalities of individuals arrested in 2004 under a law enforcement operation intended to disrupt potential terrorist threats before the presidential election.

The Washington-based group believes the operation improperly used the National Security Entry-Exit Registration System — a government database created after the Sept. 11, 2001, terrorists attacks to track visitors, students and immigrants from 25 countries — to profile Arab and Muslim visitors to the United States. The domestic registration system required males from 24 Arab and predominantly Muslim countries and North Korea to register with immigration authorities. The registration requirement has since been phased out, but the database of information still exists.

The Department of Homeland Security and the Immigration and Customs Enforcement agency issued a statement in November 2004 saying that in a one-month period, 237 people had been arrested. And, "every single one had violated immigration laws, regardless of nationality," said Dean Boyd, an ICE spokesman.

"It was simply an effort to target immigration violators who may have posed an elevated public safety threat in the weeks leading to the presidential election," he said.

Boyd said race, ethnicity and religion played "absolutely no role" in the operation.

The Arab-American organization wants to find out if the 237 people were disproportionately Arab and Muslim, because the registration database was made up of mostly Arab and Muslim men.

But the federal agency points out that in addition to the registration database, two other databases were used, including one of student visa holders.

With the national elections approaching, the group fears the registration database is being used to target Arab and Muslim men for general law enforcement purposes.

"The biggest factor is that we know that they carried out the October plan during the presidential elections — the most recent national elections we had," said Kareem Shora, the Arab-American group's national executive director. "Our fear is that since it happened during the last national elections, is something like that going to happen again soon?"

In the complaint filed Tuesday, the group does not seek names of the people detained or how they were sought out; It only requests their nationalities. The civil rights group asked for the nationality information in two FOIA requests last year but was denied.

But the Arab-American group is concerned that the registration requirements and the October arrests were presented as counterterrorism operations but instead turned into a way to enforce immigration violations.

In a letter responding to the FOIA requests, the agency said the information is exempt from the Freedom of Information Act because it was collected for law enforcement purposes and is an ongoing investigation. The civil rights group argues that getting information on just the nationalities of those detained would not jeopardize any law enforcement operation.