WASHINGTON — A federal judge ruled Monday that the National Security Agency’s bulk collection of phone records violates the Constitution’s ban on unreasonable searches, but put his decision on hold pending a near-certain government appeal.

U.S. District Court Judge Richard Leon granted a preliminary injunction sought by plaintiffs Larry Klayman and Charles Strange, concluding they were likely to prevail in their constitutional challenge. Leon, an appointee of former President George W. Bush, ruled Monday that the two men are likely to be able to show that their privacy interests outweigh the government’s interest in collecting the data. Leon says that means that massive collection program is an unreasonable search under the Constitution’s Fourth Amendment.