A National Rifle Association official apologized yesterday to law enforcement officials and others offended by a recent fund-raising letter describing some federal agents as "jack-booted thugs."

"I really feel bad about the fact that the words in that letter have been interpreted to apply to all federal law enforcement officers," NRA Executive Vice President Wayne LaPierre said in a telephone interview from Phoenix.

"If anyone thought the intention was to paint all federal law enforcement officials with the same broad brush, I'm sorry, and I apologize," LaPierre said.

LaPierre's apology comes after a week of steadily mounting criticism of the NRA, which began May 10 when former president George Bush revealed that he had resigned from the group in protest of the letter.

LaPierre said the letter was intended to criticize only isolated actions, primarily involving the Bureau of Alcohol, Tobacco and Firearms.

But at least one section of the letter offered a more general condemnation of federal law enforcement efforts.

The letter, sent to the NRA's 3.5 million members in March over LaPierre's signature, said that "in Clinton's administration, if you have a badge, you have the government's go-ahead to harass, intimidate, even murder law-abiding citizens."