Salvadoran officials said today they had heard nothing from the captors' of President Jose Napoleon Duarte's oldest daughter, as the president met with his Council of State to stress that his policies will remain unchanged.

Officials said they had only minor clues in the kidnaping yesterday of Ines Guadalupe Duarte Duran, 35. They confirmed that a friend and classmate of Ines Duarte, Cecilia Villeda, 23, had been captured along with her.

Looking drawn and tired from a sleepless night, Duarte told reporters his approach "is never the road of violence and death." He added, "I'm very sad but of course I have my duty to my country, and I'm carrying it out."

Police said they had recovered four vehicles stolen in different parts of the city yesterday, and that they believed the vehicles had been used by the kidnapers. One was the red van in which witnesses said six to eight armed men drove away with Ines Duarte and Villeda. There was no indication that anyone in the van had been wounded, they said.

Duarte's communications minister, Julio Rey Prendes, said the men who robbed one of the vehicles told the vehicle's owner that they were from the Farabundo Marti National Liberation Front (FMLM), the coalition of five leftist guerrilla groups fighting the Durate government. However, he said, the government has not yet ruled out the possibility that the kidnaping was carried out by a far right-wing group.

One bodyguard was killed in the afternoon attack, which occurred as the two women were arriving for a class in communications at a local private college. Another bodyguard remains in critical condition with gunshot wounds, while a third escaped unhurt.

President Reagan called Duarte last night and sent a letter, addressed: "Dear Napoleon," in which he expressed "our heartfelt concerns and prayers," and offered "all appropriate assets of the U.S. government" to help in investigating the kidnaping, U.S. Embassy officials said. They said that meant "technical, investigative or intelligence assistance."

Rey Prendes said the kidnaping had caused "a whole commotion" and that Duarte had received condolences and condemnations of terrorism from leaders and organizations around the world.