Human rights group Amnesty International says Mexican authorities have failed to prosecute police accused of sexually abusing women from the town of San Salvador Atenco.
Amnesty says more than 20 women have complained of being abused or raped by police who were sent to the town in May to stop a protest by local residents. The women were among more 200 people arrested and beaten by police during the riots.
Amnesty says Mexico's federal government should investigate accusations of police brutality against women during the riots. The group says local authorities are ignoring or covering up the alleged abuses, which it says amount to acts of torture.
The unrest in San Salvador Atenco began when Mexican police tried to stop protests by a small farmers' organization. Hundreds of protesters fought with police, and several officers were kidnapped.
Some information for this report was provided by Reuters.