Amnesty International has called on the Mexican authorities to protect an Indigenous community blockaded by more than 30 paramilitary gunmen with links to one of the country's main political parties.

The 700 people living in San Juan Copala, in the Indigenous Triqui region of Oaxaca state, are virtually cut off from the outside world. They have restricted access to food and electricity and the armed group has also cut their water supply. Those trying to break the blockade have been threatened, attacked or killed.

The paramilitary gang, known as Ubisort, is reportedly connected to the governing political party in Oaxaca, the Revolutionary Institutional Party (PRI). A local human rights defender and an international human rights observer were killed by Ubisort gunmen last week while on their way to help the community.

"The residents of San Juan Copala are being denied their basic human rights and the authorities must take action to ensure their safety and access to essential services, including food and water," said Guadalupe Marengo, Amnesty International's Americas deputy director.

"The government needs to halt the violence of the armed groups operating in the area which have targeted the community in reprisal for its efforts to establish a measure of self-government separate from the main political parties in the region which it blames for years of violence and neglect."

San Juan Copala, is one of the communities of the Indigenous Triqui group, one of the poorest and most marginalized ethnic groups in Mexico, declared itself an autonomous municipality in 2007. This means it governs itself through the traditional indigenous practices and does not recognize the authority of existing public officials.

Members of Ubisort, who in part come from a neighbouring Triqui community, have repeatedly fired rounds into and over San Juan Copala to terrorise the population. On 17 April, a local man was killed by members of Ubisort and the siege has intensified since.

Only the older women in the community are allowed to leave to fetch food on foot from the nearest town, while all vehicles have been turned back since early April.

The insecurity has prevented teachers and medical staff reaching the local school and health clinic, severely restricting access to education and health services.

According to reports, Ubisort also prevented damaged electricity cables from being repaired and broke the pipe delivering the community's water supply, forcing residents to use a contaminated water source.

On 27 April a group of human rights defenders, political activists and journalists tried to reach San Juan Copala to raise awareness of the siege and bring supplies of food and water.

Just outside San Juan Copala, 30 armed members of Ubisort ambushed them, killing one woman, local human rights defender Alberta Cariño, and a man, Finnish national Jyri Antero Jaakkola.

Despite repeated calls for the local and state government to take action, the siege has not been broken and no members of Ubisort have been brought to justice. In order to rescue other activists caught in the attack, the state government reportedly held discussions with the well-known leader of Ubisort,,who remains at large.

Ubisort have denied reports accusing them of being perpetrators of violence.

On 5 May, Mexico's Human Rights Commission called for protection measures to be issued on behalf of the residents of San Juan Copala.

"The Mexican federal authorities must ensure that the San Juan Copola community has access to basic supplies and prevent human rights abuses, such as killings, attacks and threats, committed by members of Ubisort," said Guadalupe Marengo.

"The armed group's links to members of Oaxaca's governing party, the PRI, must also be fully investigated."

Source: Amnesty International