Updated

A prominent human rights group has condemned the conviction of 34 people accused of rioting in Kazakhstan's western oil town last year.

Human Rights Watch said in a statement Tuesday that the court should have properly investigated claims that defendants were tortured while in custody.

Authorities insist there is no evidence that suspects were mistreated.

Thirteen people were sentenced to between three and seven years in jail Monday for their involvement in the unrest, during which at least 14 people died.

A further 16 people on trial were granted conditional sentences, five were amnestied and three were acquitted.

The unrest in Zhanaozen in December came after a seven-month long occupation of the main square by oil workers demanding higher salaries. A confrontation with police descended into rioting.