ISLAMABAD, Pakistan (AP) _ Soviet and Afghan forces have pounded villages north of Kabul with the heaviest artillery and air strikes of the year in an attempt to reach Moslem guerrillas, diplomats reported Tuesday.

Western diplomats, speaking anonymously, quoted colleagues in neighboring Afghanistan as saying the attacks during the past week could be heard in the capital and a red glow was visible in the northeastern sky at night.

They said aerial bombardments began Aug. 4-5 after several guerrilla attacks in the Khair Khana Pass, the northern entrance to the city.

Soviet-Afghan ground forces moved in with artillery last weekend, causing about 2,000 people to flee what was described as mass destruction, the diplomats reported.

Moslem insurgents began fighting after a communist coup in April 1978 installed a government allied with Moscow. The Kremlin sent military forces to Afghanistan in December 1979 and an estimated 115,000 Soviet soldiers now are in the country.

Witness reports relayed by the sources said about 1,000 refugees arrived in Kabul on Saturday, most on foot or riding donkeys.

The guerrillas, with better arms and training than ever before, have put increasing pressure on all approaches to Kabul this year.

Intensive spring military operations east of the capital apparently failed to cut guerrilla supply lines from Pakistan, where about 3 million Afghan refugees live in border camps and towns that serve as supply points.

Soviet soldiers had to dig in west of the city in July to stop insurgents advancing out of the mountains.

Diplomats in Kabul said increased fighting outside the city had caused tighter security inside, mostly in the form of foot patrols by Afghan security forces, the sources reported.

They said the Soviets had strung additional barbed wire and mounted heavy machine guns around their bases. The reports said more bricks were being added to the street side of the Soviet Embassy and workers were digging what appeared to be a moat between the wall and the road.

Reports of fighting around the country came from various sources, and a guerrilla organization based in Peshawar, Pakistan, issued a rare report of defeat.

The Islamic Press Agency, linked to the Yunis Khalis guerrilla group, said 35 insurgents were killed and 20 wounded Aug. 4 in an ambush by Afghan soldiers in the eastern part of the country.

It said the insurgents were preparing to seize a road between two military outposts but the troops surrounded them. The agency put army casualties at 24 dead or wounded.

Increased fighting north of Kabul coincided with a visit by Felix Ermacora, representative for Afghanistan of the U.N. Commission on Human Rights. He visited prisons, interrogation centers and other facilities, according to the U.N. Information Center in Kabul, and will report to the U.N. General Assembly.