GABORONE, Botswana (AP) _ Bits of wood and red clothing hung from a tree near the blown-out wreckage of a small house. A steel coffin containing the bodies of two young girls lay nearby, testimony to the ferocity of South African commando raids Friday.

The devastation at the sites of the raids reflected the tattered South African peace initiative, which some had acclaimed a year ago as a likely solution to tensions in the region.

At 1:15 a.m. Friday, South African soldiers attacked 10 houses allegedly used by members of the African National Congress, the outlawed guerrilla movement fighting South Africa's white-minority rule. The Botswana government said 12 people were killed.

South Africa said as many as 16 people were slain in simultaneous strikes in neighborhoods across Gaborone, the Botswana capital just north of the South African border.

In February 1984, South Africa signed an accord with Marxist-ruled Angola for the withdrawal of South African troops in return for Angolan help in controlling guerrillas fighting to end South African rule over South-West Africa. A month later, South Africa signed a peace pact with Mozambique, long a conduit for ANC guerrillas on sabotage missions in South Africa.

But in March this year, a bomb went off in Gaborone, destroying one house and damaging 16. In May, a car bomb killed an ANC member in Gaborone, and the government blamed South African agents.

Then, South African commandos were intercepted in Angola's Cabinda Province last month in what South Africa said was an intelligence mission. Two soldiers were killed and one captured, and Angola said they were on a planned sabotage raid against an oil refinery run partly by the American Gulf Oil Corp.

South African Defense Force Chief Constand Viljoen said after Friday's raids that his forces would strike anywhere against ''terrorists.''

The raiders came by road to the capital, about 15 minutes from the border, and witnesses said they shot ''at passing motorists and set a number of vehicles on fire.'' The commando squads set up roadblocks and scattered nails on the road as they withdrew to deflate the tires of possible pursuers.

The small Botswana Defense Force was taken by surprise, and by the time soldiers were mobilized, the attackers had vanished. Roadblocks were mounted throughout the capital during the day, but no arrests were reported.

At the house where the two girls were killed, an explosion had destroyed both of the 25-foot-long exterior brick walls, leaving only the two end walls standing.

''A five-year-old child was heard calling for his mother before the South Africans opened fire with machine guns on him and his uncle,'' Botswana Radio said. It said the mother escaped by hidinag under a bed.

A couple died in a hail of bullets in a guest room of a house, while a cousin was shot dead in a closet where he was hiding, the radio said.