President Jose Napoleon Duarte said today that his daughter was kidnaped in an effort to weaken him and thus to weaken his policies and his domestic and foreign support.

"If they kidnap a governing person's daughter, he can lose his serenity and lose everything he has struggled for for so many years," Duarte said in an interview.

Officials here said there still had been no contact from anyone claiming responsibility for the attack Tuesday, in which Ines Guadelupe Duarte Duran, 35, and a friend, Cecilia Villeda, 23, were kidnaped by unknown gunmen as they arrived for classes at a private college. One of Duarte Duran's bodyguards was killed and another was seriously hurt in the attack.

Although many here believe the attack was conducted by leftist guerrillas fighting to overthrow Duarte's government, officials said they had no proof. The president noted that he has many enemies on both sides of the political spectrum. He said he had received "a threat of a strategic plan of action against my family" in June.

At that time, he said, some said he had invented the threat to get publicity. "Now we have the confirmation," he said.

Looking very tired, Duarte denied published reports that he had suffered a heart attack or any serious illness but said he was "very sad" about the kidnaping.

"We had thought about this, that someone could kill me or one of my children, but now when the moment has become reality, it is something different," he said.

He said the many messages of support he had received from Salvadorans and world leaders "maintain me in my struggle to keep faith with my goals." The attackers, he said, had only demonstrated their moral bankruptcy.

Ruben Zamora, a leader of the guerrillas' political wing, said in Managua, Nicaragua, that he had no knowledge of the kidnaping.

"I can't say because I don't know," Zamora said. "I don't know why anyone would do it."

Zamora said any one of the five guerrilla groups in the Farabundo Marti National Liberation Front had the "personnel and the capability to pull off this kind of attack." He appeared to be worried about what might happen to Duarte Duran and what the political consequences of the kidnaping might be.

The slaying by guerrillas on June 19 of 13 persons, including four U.S. marines and two other U.S. citizens, "had negative political effects" for the guerrillas, "not only internationally, but more importantly with sectors inside the country who have supported us in the past," said Zamora.

Those groups did not object to killing the marines, who were "military and a justifiable target. It was the killing of civilians that angered people," he said.

He added that he did not believe killing Duarte Duran could be justified. "She has been kidnaped. She has not been killed," he said.

Police said that as part of their investigation of the kidnaping they had raided 12 guerrilla "safe houses" in different parts of the city during the early-morning hours, arresting an undisclosed number of persons and capturing a large cache of arms. There was no immediate proof linking any of those arrested or any of the houses to the kidnaping, one military official said.

The armed forces showed a videotape of one of the houses, a large, tastefully furnished upper middle-class home in the expensive Escalon neighborhood.

The tape showed a hole under some tiles in the living room floor where police said they had found a weapons cache. Half a dozen submachine guns, an antitank weapon, plastic explosives, a large quantity of ammunition and several tape recorders and other communications equipment were displayed for the camera alongside the house as soldiers rummaged inside.