Washington — The Soviet Union has increased its pressure on the civilian population of Afghanistan, according to Afghan and United States government sources. The sources say that over the past year the Soviets have intensified their attacks on houses, crops, and small dams. One result was a new flow of tens of thousands of Afghan refugees into Pakistan in the months of August and September.
Despite their devastating tactics, the Soviets seem to be no closer to winning the war. Afghan sources say that with the fourth anniversary of the Soviet invasion of Afghanistan approaching, the Soviet-supported Afghan Army is still unreliable and the Afghan Communist Party deeply split.
''The pressure on the civilian population is a problem,'' says Syed Bahauddin Majrooh, director of the Afghan Information Center in Peshawar, Pakistan.
''The Russians have seriously disrupted crops,'' says Dr. Majrooh, who has been visiting the United States partly under the auspices of the international visitor program of the US Information Agency. ''Because of the bombardments and the lack of population in some areas, many of the dams have not been repaired. The Russians have been burning harvests. There is a food shortage.''
Majrooh, former dean of the faculty of literature at Kabul University and former president of the Afghan Historical Society, runs a clearinghouse for Western journalists gathering information on events in Afghanistan. His center publishes a monthly bulletin that is regarded by journalists as a usually reliable source of information.
In an interview here, Dr. Majrooh said the Soviets are attacking more by air and using more mobile tactics in the fighting. He said their slow-moving land truck convoys have been relatively easy for the Afghan resistance fighters to attack. As a result, the Soviets have apparently been moving more of their equipment, even including light tanks, by air.
He said the resistance fighters now have little difficulty in obtaining light arms. What they need most, he said, are weapons that can be used against Soviet helicopters. He added that the greatest need for the civilian population was for medicine and medical facilities.
''We have told humanitarian organizations that our first priority is medical, and our second priority is medical,'' Majrooh said.
He asserted that the Soviets are trying to ''empty'' the countryside of civilians so as to reduce support for the resistance fighters. But he said that even the outskirts of Kabul, the capital, were ''practically in the hands of the resistance.''
He said the Soviet-supplied Afghan government army could not be trusted by the Soviets and that the split between the Parcham (Banner) and Khalq (Masses) factions of the Afghan Communist Party was deeper than ever. Because they could not rely on their Afghan allies, the Soviets were having to enter into the smallest details of administering the country, Majrooh said.
A US State Department official said, meanwhile, that the US had received confirmation from Several sources that Soviet planes, tanks, and artillery had destroyed more than half of the small market town of Istalef, some 20 miles north of Kabul, in raids launched Oct. 12-17. The official said there was also confirmation of reports that the Soviet troops had killed a dozen children with bayonets when they entered the town after the raids. Civilian casualties resulting from the air attacks were reported to have been high. Istalef is well known to travelers because of its blue pottery.