BANGKOK, JUNE 3 -- Cambodian authorities have tortured thousands of political prisoners in interrogations using electric shock, hot irons and near-suffocation with plastic bags, Amnesty International said today.

Prisoners have been beaten with sharp-edged wooden sticks, whipped with chains and rubber hoses and imprisoned in coffin-like cells or underground chambers, the London-based human rights organization said in a report.

Amnesty said it has reports of 34 prisoners dying after interrogation, usually because of inadequate medical care for injuries, lack of food or "grossly insanitary prison conditions."

It said people were tortured at centers throughout the country by both Cambodian and Vietnamese personnel.

Vietnam invaded Cambodia in December 1978 and ousted the Khmer Rouge government of Pol Pot, ending a four-year reign of terror in which as many as 2.5 million people died. In January 1979, Vietnam installed a new government in Cambodia.

The Khmer Rouge and two allied groups have been fighting a guerrilla war against the Cambodian Army and an estimated 150,000 Vietnamese occupation troops.

A spokesman for the organization estimated the number of political prisoners in Cambodia at about 5,000.

Premier Hun Sen of Cambodia said in an interview last week that his government had "rather a small number" of political prisoners. He said the Amnesty allegations were "an exaggeration."

According to Amnesty International, people were tortured to extract confessions or obtain information on acquaintances suspected of opposing the regime.