Saudi Arabia has told the United States in strong terms that a substantial delay in the projected sale of F15 jet fighters would force it to turn elsewhere for advanced warplanes, a State Department official said yesterday.

The statement by Deputy Assistant Secretary of State J. Brian Atwood came as Sen. Henry M. Jackson (D-Wash.) called for postponing action on all controversial warplane sales to the Middle East, and as Saudi Ambassador Ali A. Alierza sent an appeal on behalf of the F15 transaction to every member of Congress.

"A delay is just as bad as a rejection" in the view of the oil-rich desert kingdom, said Atwood, the State Department's chief lobbyist on the warplane issue. Atwood said that a six-month delay - which has been suggested by Jackson and some other congressional figures - would actually mean an effective postponement by at least a year because of congressional adjournment this fall and the time-consuming-requirements for congressional review.

Atwood said the Saudis have stated "categorically" through diplomatic channels that any delay of this magnitude would cause them to buy their warplanes elsewhere. Because of the aging condition of their present military aircraft and the passage of more than two year since the first U.S. commitment to supply more modern planes, he said, the Saudis have said "they simply couldn't tolerate another year's delay."

The most likely substitute if the U.S. deal is killed or shelved by Congress is the French Mirage F1, to be followed when it is ready by the more advanced French 2000, according to Atwood. Saudi as well as U.S. officials have said that a shift from the United States to France as the major supplier of military equipment could bring broader changes in U.S.-Saudi relations.

Jackson, at a breakfast meeting with reporters, said last weekend's Palestinian commando raid in Israel and a Saudi state radio broadcast commending it have dimmed the chances for the F15 sale, which was already in trouble in Congress. Jackson has opposed it for several weeks. "I think there's a mood [in Congress] to postpone all the jet sales. That's my feeling and it's the feeling of other senators," he said.

The Saudi Arabia Information Office, an adjunct of the Washington embassy, distributed a statement late yesterday saying that "Saudi Arabia condemns terrorism in all its forms" and adding that "those who have committed it on innocent people inevitably draw counterterrorism on other innocent people." The statement was attributed to an official spokesman of the Saudi government in Riyadh Sudi Ambassador Alireza has denied that last Sunday's radio broadcast represented the viewpoint of his government.

In a five-page statement accompanying his two-page letter to all members of Congress, Alireza said "a postponement of the decision on the [F15] sale would be extremely harmful because it would be taken as a sign by Communists and radicals that the U.S. was reconsidering its support for Saudi Arabia."

Alireza added that "since the kingdom's obsolescent Lightnings [British warplanes] must in any event be replaced, Saudi Arabia would be forced to consider alternatives, including the purchase elsewhere of existing sophisticated aircraft and the possibility of helping to finance the development by someone else of advanced aircraft comparable to the F15."

Israeli Defense Minister Ezer Weizman and other opponents of the sale to Saudi Arabia have pointed to the possibility that F15s might be stationed at the Saudi airfield at Tabuq near the Israeli border, and thus the desert kingdom could quickly become a target or combatant in a future Arab-Israeli war. Alireza's statement said that "the F15s are of sufficient importance military that they would not be placed at an advance base like Tabuq where they would constitute an inviting target."

The Saudi embassy statement to Congress made these other points:

"Saudi Arabia recognizes that its purchase of F15s is subject to the condition that their transfer to any third party without prior approval of the U.S. government is prohibited."

"The American commitment to meet Saudi Arabia's legitimate defense needs with F15s was made in 1975, endorsed by President Ford in 1976, and reaffirmed, after independent study, by President Carter in 1977 and 1978."

"Saudi Arabia possesses 25 percent of the world's proven oil reserves and has a special responsibility to itself and to the free world to assure protection of this vital resource."

"The U.S. and Saudi Arabia have come to share a special relationship on a broad range of basic matters" including $5 billion in trade this year and Saudi supply of almost one-tenth of the oil now being used by Americans.