Soviet forces have continued their massive air activity over Afghanistan as reports circulated in the Afghan capital of Kabul that they had launched a major attack against rebels in a nearby province, according to a diplomatic report received here today.

The heavy schedule of flights to and from Kabul's airport included a large number of M124 helicopter gunships, Moscow's most potent weapon against the rebel tribesmen who have bedeviled efforts to turn Afghanistan into a Marxist state.

This indicated to specialist that the Soviets had mounted a major offensive and were not merely positioning their forces for some future operation. It had been widely speculated here and in Kabul that the Soviets were holding off on any new operations until the Moscow Olympics ended.

While it was impossible to pinpoint the destination of the flights or tell what they were doing, reports reaching diplomats in Kabul said that a large force of Soviet and Afghan troops -- backed by Soviet air power -- had launched an attack on rebel positions in the province of Wardak southwest of the capital.

At the same time, the confusing and often contradictory stories reaching Kabul from travelers in the Afghan countryside tended to discount earlier reports of a battle between the Soviets and Afghan soldiers who supposedly mutinied when their commander was replaced as part of a feud within the ruling party.

"Those reports may not have been accurate," said an area specialist here who had circulated them Monday.

The reports of the mutiny and battle gained credence here because they came from two diplomatic missions that generally differ in their analyses of events in Afghanistan.

There appears to be no question that the Afghan 14th armored division headerquartered in Ghazni, the province southwest of Wardak, became discontented when their commander was replaced.

"Some elements may have defected to the insurgents. But we cannot confirm hostilities between Soviet forces and the Afghans," said the specialist on the basis of information received today.