The federal government sued the New Jersey attorney general and other state officials Wednesday to stop them from seeking information about telephone companies' cooperation with the National Security Agency. The unusual filing...is the latest effort by federal authorities to halt legal proceedings aimed at revealing whether and how often AT&T, Verizon and other phone companies have provided customer records to the NSA without a court order. New Jersey Attorney General Zulima Farber, a Democrat, and other officials sent subpoenas to five carriers on May 17, asking for documents that would explain whether they supplied customer records to the NSA, the lawsuit said. The subpoenas followed by a few days a USA Today report that the phone companies had complied with the secretive agency's request for the phone records of millions of ordinary Americans after the Sept. 11 attacks. The Justice Department said more than 20 lawsuits have been filed around the country alleging that the phone companies illegally assisted the NSA. The government says sensitive national security information would be revealed if judges allow those cases to proceed. In this matter, the federal government said the New Jersey officials are treading on federal turf and that the companies, if forced to comply with the subpoenas, would be confirming or denying the existence of the program. President Bush and other top federal officials have refused to do that.