President Babrak Karmal of Afghanistan gave up the post of prime minister yesterday and appointed one of his deputies, Sultan Ali Kishtmand, to head the government, Radio Afghanistan reported.

The announcement, monitored by the BBC, said the change was made at a session of the Afghan Revolutionary Council. The move appeared to bolster Babrak's position. The council has been dominated by Babrak's rivals, the Khalq (Masses) faction of the ruling People's Democratic Party of Afghanistan.

Since taking power in a Soviet-backed coup in 1979, Babrak, the head of the Parcham (Banner) faction of the party, was held all three top jobs in Afghan politics -- president, prime minister and party leader.

The long-promised reshuffle followed by slightly more than a week a surprise trip to Moscow by Babrak after a reported shootout in his People's Palace between leaders of the two factions. Khalq leaders reportedly have demanded that the estimated 85,000 troops now in Afghanistan leave the country.

Western diplomatic sources in India said that they had received reports from Kabul of a gunfight between members of the rival Marxist factions. The diplomats linked the reported battle with tension over the choice of a prime minister.

Babrak said in April that he wanted to hand the premiership to someone else.