Bolivia's government says the number of people killed in recent clashes between supporters of President Evo Morales and opposition groups has risen to 28, reported BBC.
Interior Minister Alfredo Rada said a further 10 bodies had been found in Pando province following the "massacre" of pro-government farmers on Thursday.
Pando Governor Leopoldo Fernandez has been accused of ordering the attack.
A state of emergency remains in the province, where troops have retaken control of the capital, Cobija.
Meanwhile, neighbouring Chile called an emergency meeting of the Union of South American Nations to help promote a democratic solution to the crisis before it spreads throughout the region.
The conflict has arisen over radical plans by President Evo Morales to re-distribute the country's wealth and give a greater voice to the large indigenous community.
It later escalated when Mr Morales expelled the US ambassador from Bolivia, accusing him of stoking anti-government sentiment. The US says the accusation is baseless.
The BBC's Daniel Schweimler in the eastern city of Santa Cruz says sporadic clashes between the two sides has continued in northern and eastern areas.
Earlier, the interior minister said a further 10 bodies had been found in Pando following Thursday's "massacre" of government supporters, in which 16 others were already known to have died.
Mr Rada said the government had ordered the arrest of Governor Fernandez, who the president accused on Saturday of hiring "Brazilian and Peruvian assassins" to carry out the "ambush".
A local farmers' leader, Shirley Segovia, told Erbol radio that the victims "were killed like pigs, with machine guns, with rifles, with shotguns, with revolvers".
The Bolivian ambassador to the UK, Maria Beatriz Souviron Crespo, told the BBC that Mr Fernandez was "acting outside of the law".
"He's provoking violence in the region. We have lost many lives. And life is very precious, for this country, for this government, and for everybody," she said.
Mr Fernandez has denied having anything to do with the deaths, insisting they were the result of clashes between rival groups.
"The government has a great ability to distort things, and its arguments are always the same - accusations without reason," he told Radio Fides.
Another two people were killed on Friday at Pando's main airfield as government troops opened fire to disperse opposition protesters.
Opposition groups are demanding that the government cancel a planned constitutional referendum on 7 December that would give more power to indigenous and poor communities by carrying out land reform and redistributing gas revenues.
They and their supporters instead want greater autonomy as well as more control over revenues of natural gas in their areas.
Mr Morales, Bolivia's first indigenous president, has denounced those leading the protests as fascist and racist elements that are determined to overthrow him.
He has also said he would not hesitate to extend the state of emergency in Pando to the other three opposition-controlled provinces in the east of the country.