Following are excerpts from yesterday's news conference with Soviet officials in Moscow on the Soviet downing of a South Korean jetliner.

Participating were Marshal Nikolai V. Ogarkov, Soviet military chief of staff; Deputy Foreign Minister Georgi Kornienko, and Leonid Zamyatin, head of the international information department of the Communist Party Central Committee.

The excerpts are taken from a simultaneous translation of the remarks provided during a live overseas broadcast of the session. The sequence of events is apparently based on Kamchatka time, three hours ahead of Tokyo and Seoul.

The session opened with a statement by Ogarkov:

The Korean plane deviated from course by about 500 kilometers 300 miles . . . The flight evidently was proceeding at all times under the surveillance of electronic devices and flight control systems controlled by the Americans.

To lose a plane under these conditions and to allow such a major deviation from the . . . accepted routes must be excluded as an error . . . . Why wasn't it corrected? This question remains unanswered still.

Why did the Korean plane's deviation . . not produce alarm among the Japanese and American ground controllers? This question remains unanswered, too . . . .

The entry of the plane into the zone controlled by the Soviet air defense occurred specifically at the point where American RC135 planes regularly operate. And on that very flight route, an RC135 was found by the Soviet forces on Sept. 1.

It was followed by the Soviet radio electronic surveillance devices. The plane operated in that area about two hours. At 4 in exactly the same area . . . another airplane was detected. At 5 the two planes rendezvoused and for some time, approximately 10 minutes, in that region they were flying side by side, then one of them . . . turned back and flew to Alaska while the second plane went straight to Petropavlovsk in Kamchatka. This led the Soviet control point to the result that an American airplane was entering the Russian airspace . . . .

Attempts to contact the plane at the fixed international frequency . . . were made and it was decided to force the plane to land on the nearest airfield. However, the intruder plane was departing in the general direction of the Okhotsk Sea.

In the third stage, the action became defiance. No matter what attempts were made, it did not respond to signals from Soviet interceptor planes. And it began to maneuver, changing speed and altitude, obviously trying to evade . . . .

At 6:02 local time . . . the intruder . . . altered his course and began approaching positions of our anti-air defense forces base. There was no doubt then it was a reconnaissance plane.

When the plane was over the southwestern portion of the peninsula, the final attempt was made to force the plane down. Four rounds of warning shots were fired. One hundred and twenty cartridges were fired. However, the plane did not yield to these signals but tried to evade in the general direction of Vladivostok.

At 6:24 local time . . . it was ordered at that specific point to cut short the flight of that plane using heat-seeking missiles . . . .

Q: Why after tracking that airplane 2 1/2 hours were your pilots unable to identify it as a 747 jumbo jet? And secondly, assuming everything the Soviet government says is correct, why did the Soviet Union then shoot down a passenger plane with 269 men, women and children aboard?

OGARKOV: I assume that you have familiarized yourself with the announcement of the Soviet Union. I think you realize why we were tracking this plane for 2 1/2 hours.

The Soviet side took every step possible to force the plane to land on one of our airfields. However, the plane stubbornly ignored all warnings from the Soviet planes and did not want to enter into radio contact. Let me point out to you that the plane proceeded in the same manner as another plane of the Korean airline that intruded in Soviet space in 1978 . . . .

The Soviet air forces made attempts to make it land but the plane evaded, altered course . . . .All possibilities were exhausted and only then was the order given . . . .

Q: While the plane was in Soviet airspace for 2 1/2 hours, what contact was made between the local control points and Moscow?

OGARKOV: . . . The Soviet air defense forces operated in full contact with government authorities . . . . The order to the pilot was given by the commander of the . . . region . . . .

Q: When did you learn about it?

OGARKOV: In the general staff we were all informed . . . .

Q: The Soviet statement of Sept. 6 said Soviet pilots could not know this was a civilian plane. Was the flight terminated by mistake?

OGARKOV: Termination of the flight . . . was not an error. Antiaircraft defense forces attempted to [force a landing] . . . . Complete conviction was achieved that we were dealing with a reconnoitering plane . . . .

Q: What hard evidence do you have that it was a spy plane?

OGARKOV: Our analysis of . . . this plane and the other aircraft in the Kamchatka area and its choice of course and direction toward significant military installations, and finally its sort of incomprehensible conduct consisting of totally ignoring all warning signals . . . . And let me add that at all command levels we reached the total conviction we were dealing with a reconnaissance plane and we were trying to force it to land in Kamchatka and when it did not react to 120 warning shots nothing was left . . . .

Why was their RC135 aircraft accompanying the aircraft to confuse the Soviets? . . . We do not exclude the possibility that it was controlling the Korean plane . . . . We are not referring to an error here . . . . It was an aircraft sent on a special mission.

We dragged on our activities for 2 1/2 hours and it was only when we were convinced we were dealing with a reconnaissance airplane totally ignoring our defense forces, what was left to us? . . .

What kind of evidence is needed, considering the plane was off course 500 kilometers? What other evidence do you need?

Q: Could the plane have passed important information during its 2 1/2-hour flight?

OGARKOV: That is known only to the pilot . . . . His communications were by short radio signals and the content of those short radio signals is not known.

Q: The 747 is easy to identify. How could the Soviet radar operators and pilots confuse the 747 with another plane?

OGARKOV: . . . It's similar in silhouette to other airplanes. It's easy to sit here and compare the silhouette of one airplane with another. However, the contact of those planes was in the dark of night and it's difficult in those circumstances to tell differences and similarities. So it's quite possible that the silhouette of one plane could be mistaken for the silhouette of another . . . .

Q: If the Soviet Union bears no guilt in this affair, as you have said today, why have you not yet told your own people that 269 people died?

OGARKOV: How would we know how many people were on board on the plane? We were not estimating at all that we were dealing with a passenger plane. We were dealing with a reconnaissance aircraft. Why should we report there were so many people aboard? . . .

Q: Do you think that the protection of the sacred borders of the Soviet Union was worth the lives of 269 persons aboard the jetliner?

KORNIENKO: Protection of the sacred inviolable borders of our country and our political system was worth to us, as you know very well, many, many millions of lives . . . .

Q: Why did the Soviet pilot receive the order to terminate the flight after seeing the light signals from the Korean jetliner?

OGARKOV: The Soviet pilot didn't see the lights. He fired warning shots and only after the Korean failed to react he fired.