President Kenneth Kaunda said yesterday that 1,000 South African and Rhodesian troops are attacking Zambia in an escalation of the frequent border crossings by the two nations, Washington Post correspondent Jay Ross reported.

In a radio interview, Kaunda said 600 South African soldiers were in the western province bordering South African-controlled Namibia and another 400 Rhodesian troops were fighting in the southern Zambezi valley.

Zambian forces have clashed with the invaders and "our boys with limited means are containing them" Kaunda said Tuesday night in first disclosing the incursion at a dinner for an Iraqi delegation. "It is not an easy thing, but we are holding our own," he said.

The South Africans and Rhodesians crossed the border last week and the fighting is continuing, Kaunda said.

In Salisbury, Zimbabwe-Rhodesian military headquarters said its ground and air forces attacked guerrilla positions inside Zambia in an operation that began Sunday and had now ended.

Zambian officials could provide no details about casualties, the number of Zambian forces involved or the level of the fighting against the South Africans and Rhodesians.

Diplomatic sources said they believed that much of the fighting is being done by Rhodesian and Namibian guerrillas whose forces are located in Zambia and who have frequently been attacked by the Zimbabwe-Rhodesian and South African military.

Kaunda referred only briefly to the clashes in his speech Monday night and declined to provide more details yesterday. This led observers to believe that the Zambian military is not involved in large-scale fighting. Nevertheless, Kaunda's statement was the first public acknowledgement of simultaneous fighting on the western and southern fronts by Zambian forces.