Angolan President Jose Eduardo dos Santos said today that he does not share expressed American optimism that a Namibia settlement is near. He blamed the delay on "a very persistent attempt by the United States" to link the issue to a withdrawal of Cuban troops from Angola.

Dos Santos' statement, the most pessimistic yet from African leaders involved in the latest diplomatic initiative, followed an assessment yesterday by envoys in South Africa that it had reached a deadlock.

Speaking at a press conference at the end of a four-day visit to Zimbabwe, the Angolan leader accused "the United States of trying to change an Angolan problem into an international problem." Such an approach, he said, was "absolutely unacceptable."

Starting in June, senior State Department officials began speaking optimistically about the possibility of implementing a United Nations plan for independence of Namibia, controlled by South Africa in defiance of the world organization.

Throughout a series of meetings with Angolan officials, the State Department has maintained the upbeat stance, predicting at one time a cease-fire in the 17-year-old independence war as early as mid-August.

In the last month, however, the African nations supporting the guerrillas have more actively opposed U.S. demands that South Africa's departure be matched by Cuban withdrawal from Angola.

It is estimated that there are 15,000 to 20,000 Cuban troops in Angola and perhaps twice that many South African soldiers in Namibia, the last colony on the African mainland. South African troops there frequently invade neighboring Angola, allegedly because of the presence of guerrillas of the South-West African People's Organization fighting to control Namibia.

Dos Santos acknowledged that some progress had been made on reaching agreement on the U.N. plan, known as Resolution 435. But, he added, "we cannot share the same American optimism because we have observed there is a very persistent attempt by the U.S. government in bringing a strange element to Resolution 435 which naturally is difficult and complicates the advancement of the negotiations."

In this reference to the Cuban-troops issue, he also rejected any linkage of Cuban withdrawal to the normalization of U.S.-Angolan relations. The United States has refused to recognize the Marxist government, which won a three-sided guerrilla war after the collapse of Portuguese colonialism in 1975.

Zimbabwean Prime Minister Robert Mugabe joined dos Santos in condemning the U.S. and South African demands for removal of the Cuban troops that assisted the Marxist faction in gaining power.