BEIRUT, Lebanon (AP) _ Three remaining Soviet Embassy employees released by their captors one month after their abduction appeared in good health and didn't have scars or bruises to indicate they were mistreated, a Soviet diplomat said today.

A police spokesman, who spoke on condition of anonymity, also described today how the three Soviets were released late Wednesday in Moslem west Beirut. The freed Soviets are press attache Oleg Spirin, commercial attache Valery Mirikov and embassy doctor Nikolai Sversky.

A fourth Soviet also kidnapped Sept. 30 was killed by his captors shortly after his abduction. The body of consular secretary Arkady Katkov, 32, was found in a garbage dump in south Beirut two days after he was abducted.

Prime Minister Rashid Karami today lauded the release of the three and said the government was working to free Western kidnap victims, including six Americans.

Soviet Charge d' Affaires Yuri Souslikov told reporters outside the embassy that none of the men ''had any scars or bruises to indicate they had been physically mistreated during captivity.''

When asked if they will be flown to Moscow, Souslikov said: ''They're at the embassy. They're tired and we're waiting for the doctor's instructions.''

The police spokesman said the three were driven to a crossroads about 100 yards from the embassy's main iron gate at 7 p.m. (12 noon EST) Wednesday and set free.

''As the kidnappers sped away, the freed Soviets in track suits walked barefooted into the embassy, taking Charge d' Affaires Yuri Souslikov and his staff by surprise,'' the spokesman said after visiting the embassy.

The pro-Syrian Beirut daily al-Sharq said today Katkov was shot and killed because he tried to escape, but it gave no details.

''We are happy that they have been released,'' Karami told The Associated Press in a brief interview at his west Beirut residence. ''We hope that all other hostages will be freed in the near future.''

Karami was asked whether the government was making efforts to secure the release of Western kidnap victims in Lebanon, including six Americans, four French citizens, one Briton and one Italian.

He said: ''There is no doubt that the government is carrying out its duties with various parties involved in the case of releasing all the hostages.''

Karami did not elaborate.

Souslikov was asked why he thought the Soviets were released while the Westerners are still being held hostage. He replied: ''Maybe it's because we have many friends in Lebanon and Syria.''

The leftist Beirut newspaper As-Safir credited the release of the Soviets to Brig. Gen. Ghazi Kenaan, head of Syrian military intelligence in Lebanon. Kenaan arrived in west Beirut from his east Lebanon headquarters 48 hours before the release of the hostages.

He met with Justice Minister Nabih Berri, leader of the Shiite Moslem Amal militia, and senior officials of Druse warlord Walid Jumblatt's Progressive Socialist Party.

The two factions control west Beirut and its southern suburbs. Jumblatt's militiamen have been guarding the Soviet embassy since the kidnappings.

Statements delivered to Western news agencies Wednesday said the kidnappers freed the three Soviets ''to prove our good intentions.''

The statement by the Islamic Liberation Organization, believed to be made up of Sunni Moslem fundamentalists, made no mention of Katkov.

When the four were abducted, anonymous telephone callers claiming to represent the Islamic Liberation Organization said they were kidnapped to pressure Syria, the Soviets' major ally in the Middle East, to call off an offensive by leftist militias against Sunni fundamentalists in the northern port of Tripoli.

A cease-fire was declared the day after Katkov's body was found.

Most of the kidnappings of Westerners in Lebanon are believed to be the work of Shiite Moslems who are not connected to the kidnappers of the Soviets.

Sondra McCarty, a State Department spokeswoman in Washington, said Wednesday the United States welcomed the release of the Soviets.

''We also call upon those holding the American and other foreign hostages in Lebanon to release them forthwith. We've said on a number of occasions that violence such as kidnapping is outside the bounds of civilized behavior,'' she said.

U.S. officials ''are working on the presumption that they (the six kidnapped Americans) are all alive,'' she said.

Islamic Jihad, a shadowy Shiite group seeking the release of 17 comrades jailed in Kuwait for bombing attacks, claimed Oct. 4 that it had killed U.S. diplomat William Buckley, one of the six kidnapped Americans.