WASHINGTON--Defense Secretary-designate John G. Tower said yesterday that he is not on alcoholic and issued an extraordinary pledge not to take a single drink if he is confirmed by the Senate to head the Pentagon.

As Tower defended his reputation in nationally-televised interviews, Senate Armed Services Committee

Chair Sam Nunn (D-Ga.) accused the White House of leaking information from the FBI report on Tower and threatened to reopen the hearings on the nomination and subpoena anonymous witnesses quoted in the agency review.

The committee voted 11-9 along party lines Thursday to recommend that the full Senate reject Tower's nomination, with Nunn citing allegations of excessive drinking by the nominee.

In his first interview since the vote, Tower denied that he was an alcoholic and sought to allay fears among his former colleagues and remove the obstacles to his confirmation with his unusual promise.

The full Senate is expected to take up the nomination on Wednesday.

"Noting the principal concern of Senator Nunn and other members of the Senate relative to my confirmation as Secretary of Defense, namely the extent to which I may engage in excessive use of beverage alcohol, let me state that I have never been an alcoholic nor dependent on alcohol," Tower said in a statement he read on ABC-TV's This Week With David Brinkley.

"I hearby swear and undertake that if confirmed, during the course of my tenure as Secretary of Defense, I will not consume beverage alcohol of any type or form, including wine, beer or spirits of any kind," he said.

Tower distributed copies of the statement after reading it on the air. Dated Saturday, it was signed by Tower and witnessed by his doctor at Baylor University, Dr. Warren Lichliter, and Department of Transportation Secretary Samuel K. Skinner.

Tower also vowed that if he broke his pledge not to drink, he would step down.

Following the interview, Tower was asked whether it would be all right for reporters to follow him, as they did former presidential candidate Gary Hart, whose bid for the presidency was derailed by his liaison with a part-time model.

"Look, a secretary of defense lives in a goldfish bowl. If anybody wants to put a tail on me, they can," Tower said.

In the interview, Tower read a portion of a letter from Lichliter that said tests that were conducted prior to his surgery to remove a colon polyp foundnormal liver functions, and that there was noevidence of alcohol withdrawal following theoperation.

"Based on this fact that can be stated withrelative certainty, Senator Tower shows noevidence at all of alcoholic impairment oralcoholism," the letter said.

Tower conceded that there was a point in hislife when he changed his drinking habits, and inan unprecedented display by a former senator, theonetime chair of the Armed Services Committee andU.S. arms control negotiator described his pastlifestyle to the nation:

"Twelve years ago, I gave up spirits. I used tobe a pretty good scotch drinker. I haven't tastedscotch in 12 years. After that I had only wine,and perhaps an occasional martini, occasionally alittle vodka with smoked salmon, caviar, somethinglike that. That was just occasionally.

"I really essentially [have] been a winedrinker. Now my only consumption is wine at meals.I don't drink wine...unless I'm eating.