Taking the offensive again, the National Rifle Association is warning its members of an impending "police state" and urging them to attend town meetings with lawmakers to denounce President Clinton's policies.

      The 3.5 million-member NRA, one of Washington's most powerful lobbies, is using postcards to lawmakers in its drive to repeal the ban on assault-style firearms enacted last year.In response Tuesday, a gun-control advocate called the organization's leaders "fear mongers" and "extremists."

      The letter to members, which also urges them to give money, comes as the NRA is embroiled in controversy over an earlier fund-raising letter that called federal law enforcement officers "jack-booted government thugs."

      NRA chief lobbyist Tanya Metaksa writes in the new letter: "Before Bill Clinton pushes legislation that takes away from our freedoms and creates a police state, we've urged that members of Congress hold town meetings in their home districts to hear what you have to say, first."

      Like the earlier appeal, the letter sharply criticizes federal law enforcement agents, specifically the FBI and the Bureau of Alcohol, Tobacco and Firearms.

      "In the wake of the horrible tragedy in Oklahoma City, our opponents now want to expand their attacks on us to include our First Amendment rights, too," Metaksa wrote. "The right to keep and bear arms, the right to free speech and the right to free association are all on the chopping block."

      Sending postcards to congressmen about town meetings, the letter said, will help to bring a repeal of last year's ban on assault-style weapons, "to crack down on intimidation and harassment by Clinton's agents (and) to retake constitutional freedoms lost in the last two years."

      Asked Tuesday about the renewed use of strong anti-government language such as the "police state" reference, Metaksa said in a telephone interview from Phoenix: "This is so silly. Pretty soon nobody can write anything. . . . We're saying that the president is using his agencies to harass and intimidate law-abiding gun owners."

      Rep. Charles Schumer, D-N.Y., a chief author of the assault-style weapons ban, said the letter shows the NRA is using "the same kind of inflammatory language."

      "Once again, even after Oklahoma City, the NRA is pushing visions of Nazi Germany and jack-booted thugs," Schumer said at a news conference. "The leadership of NRA are fear mongers of the worst kind."