UPDATE 3-Over 30 dead in worsening Peruvian Amazon clashes

* Protesters, police dispute who shot first at roadblock

* Indigenous leader calls killings genocide

* Protesters dig in, taking 38 police as hostages

* Threat to torch Petroperu pumping plant (Recasts, adds police hostage)

By Terry Wade and Marco Aquino

LIMA, June 5 (Reuters) - Up to 31 people died and dozens were injured in clashes on Friday between Peruvian police and Amazon tribes protesting against government efforts to lure foreign energy and mining companies to the rain forest.

In the worst unrest to hit President Alan Garcia's current government, 22 protesters and nine police officers died, tribal leaders and the interior ministry said.

Angry protesters responded by saying they had taken a group of police hostage near an oil pumping station belonging to state-owned Petroperu. They threatened to set it ablaze unless police called off efforts to break up demonstrations in the Amazon basin.

"We have taken 38 police hostage," Carlos Huaman, a protester, said on RPP radio. "There are 2,000 of us and we are ready to burn the station."

The conflict, which has prompted calls for Garcia's prime minister and interior minister to quit, has underscored deep divisions in Peru between wealthy elites in Lima and poor indigenous groups in the countryside.

Critics say the government has not done enough to lower the poverty rate from 36 percent and that economic boom times enjoyed before the current downturn failed to reach the poor.

"I hold the government of President Alan Garcia responsible for ordering this genocide," indigenous leader Alberto Pizango told reporters in Lima as the government issued a warrant for his arrest for encouraging the protests.

HELICOPTER ATTACKS CHARGED

In the violence on Friday, indigenous leaders said police shot at hundreds of protesters from helicopters to end a roadblock on a remote jungle highway 870 miles (1,400 km) from Lima, the capital.

Police accused protesters of firing first, but the tribesmen denied having guns and said they only carried their traditional spears.

Thousands of Amazon natives, demanding more control over natural resources, have intermittently blocked roads and waterways since April to try to force the government to revoke a series of investment laws passed last year and to revise concessions granted to foreign energy companies.