Afghan government troops killed at least 300 Moslem rebels in two separate battles, Soviet reports said, and the guerrillas responded with a missile attack on the capital of Kabul, killing three people.

The Soviet news agency Tass, reporting in the wake of Moscow's decision to suspend its scheduled troop withdrawal from Afghanistan, said the rebels fired three missiles at the capital early Sunday but gave no casualty figures."This morning, extremists from the irreconcilable Afghan opposition again rocketed Kabul," the news agency said. "Three ground-to-ground missiles were fired at the capital. There are no data on casualties and destruction for the time being."

Afghanistan's state-run Kabul Radio, however, reported that three people were killed and seven were wounded in the rocket attack.

Kabul Radio said two missiles landed near the West German and Japanese embassies, killing two civilians and wounding two others, while a third rocket exploded in a second residential district, leaving one person dead and five wounded.

The radio broadcast also said rebel shelling of the besieged southern city of Kandahar on Sunday killed two other people, and rocket attacks for the past three days on the town of Maidan Shahr, 18 miles southwest of the capital, wounded eight and caused extensive property damage.

Tass said Afghan soldiers clashed with rebels in the suburbs of Kandahar and two other "settlements" over the past three days during which at least 153 guerrillas were killed, 43 were wounded and 19 vehicles with military hardware were destroyed.

Farther west, near Zabol in the Iranian border area, Tass said battles between rebels and troops during the same period killed at least 150 more rebels and wounded 52 others, "including a Pakistani adviser."

Tass did not say exactly when the battles took place, but the brief dispatches underscored a deteriorating situation in the country the Soviets invaded in December 1979.