At least 30 people have died in the Peruvian Amazon during clashes between police and indigenous groups protesting against oil and gas exploration on ancestral lands.

Violence erupted when police attempted to clear a road blocked by thousands of indigenous Peruvians protesting against a law they say makes it easier for foreign firms to exploit their lands.

Protest leaders said police opened fire from helicopters with bullets and
tear gas, while police said protesters attacked officers with firearms.

The confrontation began before dawn on Friday in Bagua in the rainforest where companies want to develop oil and natural gas projects, according to media reports.

"I hold the government of [Peruvian] President Alan Garcia responsible for ordering the genocide," indigenous leader Alberto Pizango told journalists in Peru's capital, Lima, on Friday.

Garcia, who wants to increase foreign oil investment in the Amazon, accused Pizango of "falling to a criminal level. Assaulting a police post, grabbing arms from police, killing police who are fulfilling their duty''.

Rights group Amazon Watch on Monday condemned what it described as a "violent raid" by police, saying witness reports indicated the unarmed demonstrators were attacked by police while sleeping alongside a road.

It also said some wrestled guns off police officers and fought back "in self defence".

Protesters 'insurgency'

Demonstrations erupted in Peru's native communities in response to government moves to open the region to oil exploration and development by foreign companies under a set of measures that Garcia signed in 2007 and 2008.

Alberto Pizango, centre, accused the government of "genocide" [EPA]

Protesters from a movement of 65 indigenous groups had declared an "insurgency" against the government for refusing to repeal the laws that threaten their ancestral land and resources. They later withdrew their decision.

The indigenous groups were backed by the International Federation of Human Rights, which groups 155 human rights organisations from around the world.

It called on Peru to rescind the decrees because of the government's failure to consult indigenous peoples.

Government officials acknowledge that the country's indigenous groups have historically been marginalised, but insist that Peru's constitution makes the state the owner of the country's mineral wealth.