More than 400 people were injured as soldiers opened fire during protests in the city of El Alto, near La Paz, the seat of the government, over the export of Bolivian natural gas.

Bolivia's Attorney-General Mario Uribe said justice had been done - and he hoped other former government officials could be tried soon.

Families of the victims cheered outside the court when the verdict was read, after having waited almost eight years in what is being considered a landmark case for Bolivia's human rights record.

The Bolivian government has been seeking the extradition of at least eight former officials - the then President Gonzalo Sanchez de Lozada, and seven former ministers. They are living abroad or have gone into exile in the US, Peru and Spain.

President Sanchez de Lozada left the country before the end of his second term in office after the killings. He has been living in the US ever since.