Afghan guerrillas fired rockets across the Afghan border into Soviet territory, killing up to 12 people, and the Soviets retaliated with air raids that killed dozens of insurgents and civilians, the guerrillas reported Tuesday.
Officials of Muslim guerrilla groups based in Pakistan said their forces made the attack about two weeks ago, firing heavy ground-to-ground rockets across the Amu Dar'ya River.
It was the first report of a direct insurgent attack on Soviet territory in several years.
Large Underground Base
Meanwhile, a Western diplomat said that the Soviet Union is building a large underground military base in southern Afghanistan near the Iranian border.
The diplomat quoted "diplomatic sources" in Kabul as saying that Soviet troops are building the base at Dasht-e-Margow, 500 miles southwest of Kabul in Helmand province.
He said the base was almost completely underground in the mostly desert area.
Guerrillas began their rebellion after the Communist takeover of April, 1978, and the Kremlin sent military forces into Afghanistan in December, 1979. An estimated 115,000 Soviet soldiers now are in the mountainous nation bordering on Pakistan and Iran.
Rocket Attack Reported
Western diplomats said privately that they have had reports of guerrillas making a rocket attack on Soviet territory, but they had no details.
Guerrilla officials in Islamabad, however, said the rockets were fired from the Imam border district and that up to 12 people were killed and several buildings damaged in Soviet territory. Soviet forces responded by bombing nearby Afghan villages, they said.
At least 22 rebels were killed in fighting after Soviet helicopters landed commando units on the Afghan side of the river, they added.
Borders Heavily Defended
Soviet border areas are heavily defended. Western intelligence sources say the frontier is guarded by at least 60,000 Soviet soldiers not included in the estimate of Soviet strength inside Afghanistan.