Israeli Prime Minster Shimon Peres said yesterday that he welcomed Syrian President Hafez Assad's comments in an interview in which Assad sought to lessen tension building between their countries for the last several weeks.

But the Israeli leader dismissed Assad's assertion that Syria had no role in an aborted attempt to put a bomb aboard an El Al airliner April 17, saying he would be "very much surprised if it was done without his knowledge."

Israel has accused Syria of supplying explosives and logistical support to a Jordanian arrested in London in connection with the incident.

Peres, appearing on CBS' "Face the Nation," was commenting on an interview with Assad published yesterday in The Washington Post. In it, the Syrian president said that neither country had introduced unusual troop movements in recent days and that he thought tensions with Israel were decreasing.

Peres took issue with Assad's assertion that Syria as a policy condemned "hijacking or exploding of civilian aircraft," charging that Syria backs "quite a collection of terrorist organizations either on their land or under their control" involved in such acts.

He said he had read "with a smile" Assad's denial that the organizations of Abu Nidal, perhaps the Arab world's foremost terrorist, and others mount terrorist operations from Syria.

Assad also had said he could not force Abu Nidal to close his camp in the Syrian-controlled area of southern Lebanon and would allow him to continue operating an office "doing cultural and political work" in Damascus.

"I must say I didn't read any book of philosophy that was published by the Abu Nidal organization," Peres said. "But we see a lot of murderous and violent actions that it took."

Peres also dismissed the Syrian leader's contention that he could not control such groups. Peres charged that a Syrian intelligence unit is "engaged directly in supporting acts of terror" and that he could "hardly think of anything in Syria which is not under the control of Mr. Assad."

Commenting on Assad's denial of a Syrian link to the El Al incident, Peres said Assad ran his country "singlehanded, and I would be very much surprised if it was done without his knowledge."

Peres said Israel does not intend to retaliate or make war against Syria because the struggle against terrorism has now become an international one with U.S. involvement.

"You have a much wider choice of means in order to impress the countries which are engaged in terror to stop it," he said, adding, "for example, economic pressure, diplomatic, public opinion and so on.

"The fact that Assad for the first time found it necessary for him to explain his position to the American public opinion shows that he understands there is a price to violence, not just an advantage to it," Peres said.