MOSCOW, SEPT. 4 -- Mathias Rust was sentenced to four years in a Soviet prison camp today, climaxing a saga of interrogation, military upheaval and admiration he set in motion with a daredevil flight across Russia to Red Square in May.

As a Soviet judge read the verdict, the 19-year-old West German amateur pilot's face flushed, but he remained calm.

"I'm feeling fine," he later told journalists in the packed courtroom. "The punishment is correct."

Rust, wearing glasses and a dark blue suit, exchanged kisses, handclasps and conversation with his mother, father and younger brother in the wood-paneled courtroom before Soviet policemen led him away.

Asked in a brief appearance on Soviet television tonight if he had expected such a sentence, Rust said, "I was prepared."

{Many West Germans reacted with shock and dismay to the sentence, but expressed hope that the Kremlin would soon release the young man from Hamburg. The Foreign Ministry said it was waiting for a full report of the trial from its Moscow embassy, Reuter reported.}

Although the official Soviet news agency Tass stressed that the sentence is "final and not subject to appeal," western diplomats close to the case speculated that Rust would be pardoned in a matter of months.

Sending Rust to prison camp for four years -- a harsh punishment by western standards -- demonstrates the severity with which the Soviet Union views violations of its borders and monuments, western observers in Moscow said.

In its summary of the verdict, Tass charged Rust with displaying "blatant disregard for the society, rights and traditions of Soviet people."

In his three-day trial before the Soviet Supreme Court, Rust was charged with hooliganism, breaking flight rules and entering the Soviet Union illegally.

He was found guilty on each count and given a total of nine years, to be served concurrently over a four-year period, in a general regime penal camp, the least harsh of the four categories of Soviet labor camps.

There are special camps for foreigners, but there was no indication today of where Rust would be sent.

Judge Robert Tikhomirnov read a summary of the evidence against Rust before reading the verdict this afternoon.

The court had taken into account Rust's age and repentance, he said.

Rust, who had earlier rejected the hooliganism charge, begged for the court's mercy in a closing statement this morning.

"I am very sorry," he said. "I would like to appeal to you, and I can guarantee that if you give me a mild punishment, I will not betray your trust."

Vsevolod Yakovlev, the Soviet lawyer assigned to defend Rust, backed up the appeal with a ringing call for a minimal sentence.

Rejecting accusations that Rust had espionage or other sinister motives, Yakovlev said, "There was no espionage, there was no adventurism and there were no young women" he was trying to impress.

"Rust is a good person," he said during 35 minutes of closing remarks. "Rust is a really interesting person. Rust is no egotist."

The grim and formalistic court proceedings here this week were in "There was no espionage, there was no adventurism and there were no young women" he was trying to impress.

-- Rust Attorney Vsevolod Yakovlev

marked contrast to the lighthearted and openly admiring reaction that Rust's mission aroused in the West.

In informal conversations today in front of the Supreme Court building where the trial was held, Soviet spectators said that Rust should get off with a fine and light sentence due to his age.

Even before the trial opened Wednesday, the facts of Rust's May 28 flight were well established. Taking off from Helsinki in a light Cessna plane, he crossed the Estonian border and flew into the Soviet Union, ending with an early-evening landing at the edge of Red Square.

The trial left Rust's motives a matter of dispute, however.

Rust and his lawyer said he had set off on a peace mission, with hopes of attracting the attention of the Kremlin leadership and meeting with Soviet leader Mikhail Gorbachev. Soviet officials dismissed the explanation. "Attempting to find some excuse for his rash flight," Tass said, "Rust claimed it was a peace mission." But the real aim of the flight, it added, "was to seek publicity and make it into the book of world records."

Prosecuting attorney Vladimir Andreyev labeled Rust a "hooligan" and accused him of endangering lives, not to mention dishonoring the Soviet Union's most hallowed sites, including the Kremlin and the Lenin Mausoleum. "He got four years," Andreyev said in leaving the court today. "I had asked for twice that."

Although Rust's Red Square landing led to the dismissal of defense minister Sergei Sokolov and other senior officials, no military witnesses were called during the trial.

The trial brought the tall, wiry and clean-cut Rust out of the KGB prison in Moscow where he was kept for three months after his flight and thrust him into an international spotlight for the first time.

His remarks in praise of Soviet policy bore the earmarks of coaching, spoken in monosyllabic German.