Immigration organizations are banding together in an effort to fight local police pursuits of immigrants , now being conducted as part of the terror war.

Taking on a job traditionally done by federal agents, a small number of police departments has begun arresting people accused of civil violations of immigration law, like overstaying visas, since the Justice Department announced its new interpretation of existing laws last year, officials say. Officials say the change was necessary to provide assistance to federal immigration officers and to remove criminals and potential terrorists from the streets. But the Justice Department has refused to release the documents on which it based its decision to advocacy groups, who say the decision violates the law and undermines confidence in local law enforcement.

A federal lawsuit against the Justice Department will be filed Monday by seven immigration advocacy groups, seeking to compel the Justice Department to turn over its records.

In 1996, the Justice Department's legal counsel decided that local police officers were precluded from tracking and arresting illegal immigrants. Such matters were to be handled by federal immigration officials. That decision was reiterated in a memorandum in November 2001.

In a letter to the National Immigration Forum last month, Attorney General John Ashcroft said his legal counsel had determined that immigrants who were deportable under immigration law and posed threats to national security could be arrested by local law enforcement.

Mr. Ashcroft said the names of such immigrants were being entered into the Federal Bureau of Investigation's database.

Police Chiefs in Texas, California, Florida and Colorado have opposed the policy saying that it threatens to undermine relations with immigrants and may make them less likely to report crimes.

The ACLU is filing the lawsuit on behalf of the seven groups. Bottom line: "There is no justification for secret lawmaking."