Prosecutors and defense lawyers for a former Chicago gang member accused of plotting with terrorists to detonate a radioactive "dirty" bomb are squabbling over a government report on the case that officials want to keep secret.

Lawyers for Jose Padilla are asking a federal judge not to review the document because prosecutors have refused to show it to them. U.S. District Judge Michael Mukasey asked prosecutors and defense attorneys to submit arguments on the issue.

The government argues that disclosing the document's contents could hurt ongoing investigations and national security interests.

The dispute, revealed in court filings made public this week, may be holding up a ruling on whether Padilla's detention is legal, the New York Times reported today.

Padilla, a U.S. citizen, was arrested May 8 on a material witness warrant issued by a grand jury and has been held in a Navy brig since June, when he was declared an "enemy combatant." The government says that declaration allows it to hold him without formal criminal charges.

The government says Padilla twice met with senior al Qaeda operatives in Pakistan in March and discussed a plot to detonate a radiological weapon in the United States.

A six-page unclassified version of the classified document has been released, but government officials concede that some confidential sources have not been entirely forthright and that some of the information remains uncorroborated.

Padilla's lawyers, Donna Newman and Andrew Patel, who contend Padilla is being held illegally, told Mukasey a hearing was needed "given the possible misrepresentation of facts by the government sources."

They said they would undergo security clearance to gain access to the classified filing, but the government has said access should still be denied, the Times reported.