LA PAZ, Bolivia (AP) _ Opposition politicians on Thursday criticized a U.S. request for the extradition of three suspected drug traffickers, saying it violates Bolivian sovereignty and may lead to drug-related violence.

The Foreign Ministry reported Wednesday that the U.S. request for the extraditions of the mother, sister and brother of Roberto Roca Suarez. Considered Bolivia's most important cocaine trafficker, Roberto Roca Suarez is being held in Los Angeles pending his trial on drug trafficking charges.

The Foreign Ministry communique said the three have been arrested, and the head of the anti-narcotics police, Gen. Elias Gutierrez said they are undergoing questioning.

The U.S. request was the first formal request by the United States for the extradition of suspected Bolivian cocaine traffickers. The Supreme Court is to rule on the request.

Roca Suarez's mother, Blanca Suarez Gomez; a sister, Beatriz Roca Suarez; and a brother, Rafael, face drug trafficking charges in San Diego.

Rep. Guillermo Richter, a leading member of the main opposition Nationalist Revolutionary Movement, said the U.S. request ''violates Bolivia's sovereignty.''

''It expresses lack of confidence in Bolivia's justice system and shows the level of the United States embassy pressures on the government,'' Richter said.

Other opposition politicians warned the request may lead to drug-related violence in Bolivia.

In Colombia, the government's decision to resume extraditions of traffickers in 1989 prompted attacks by traffickers that killed hundreds. Under a new Bogota government plan, drug traffickers who turn themselves in receive lighter sentences in special prisons and avoid extraditions.

In recent months, Bolivia has refused to sign an extradition treaty with the United States covering drug trafficking.

Foreign Minister Carlos Iturralde has said the treaty is unnecessary, because both Bolivia and the United States are signatories of the Vienna Convention, which allows the extraditions on drug trafficking charges.