Bolivian President Evo Morales lashed out at opponents on Monday after four people were killed in violent protests against his reforms and opposition leaders renewed threats to secede from the central government.
Violence exploded on the streets of the southern city of Sucre over the weekend after Morales' leftist allies pushed a draft of a new constitution through a constitutional assembly under military guard.
The US Department of State and the UN expressed concern over the violence and urged both sides to show restraint and tolerance.
Morales has made rewriting the constitution a pillar of his reform agenda, but the issue has deepened ethnic and regional divisions in South America's poorest country, which has a long history of political upheaval.
A close ally of Venezuelan President Hugo Chavez, Morales took office as Bolivia's first indigenous president in January last year, vowing to increase state control over the economy and empower the poor, Indian majority.
He nationalized the natural gas industry and seeks to give more autonomy to indigenous groups with the new constitution.
In the opposition stronghold of Santa Cruz, the country's economic powerhouse in the east, residents rallied in the main square on Monday and voted in a public forum to authorize a civic committee to declare autonomy.
Flanked by the Santa Cruz mayor and the regional governor, Branco Marinkovic, a leader of the Santa Cruz secessionist movement, said the afternoon rally gave him "a mandate" to begin the autonomy process.
Morales spoke heatedly against anti-government protesters in Santa Cruz who occupied state offices and said his government was trying to work for change for everybody.
"Occupying state offices isn't democracy, civil disobedience isn't democracy, and we hope the Bolivian people ... identify these traitors, the people who are against the nation and want to damage this process of change," Morales told thousands of followers in La Paz.
Four people were killed in the weekend's unrest in Sucre, in which demonstrators torched police stations and stormed a jail, freeing 100 inmates.
A funeral for two of the dead turned into an anti-government protest in Sucre, 700km south of La Paz, as the government contemplated emergency measures to bring the city of 200,000 people back under control.
Meanwhile, the UN, the Organization of American States (OAS) and the US, called for calm.
In New York, UN Secretary General Ban Ki-moon urged all sides to refrain from violence.
"In order to strengthen democracy and respect for human rights in Bolivia, the secretary general urges all political and social actors to remain calm, to abstain from using violence and to seek a consensus on the pressing issues affecting the Bolivian people," his press office said in a statement.
OAS Secretary-General Jose Miguel Insulza stressed the need to end the violence and the confrontations and that "the parties, given the democratic legitimacy of the Bolivian government, reinstate talks to reach a constitutional decision that harmonizes the interests of all."
"The confrontations reveal a worrying division of Bolivian society which seriously affects the environment that should reign during the drafting of a constitutional charter," Insulza said in a statement.
In Washington, State Department spokesman Sean McCormack said the US government deplored the violence and urged the Morales administration and the opposition "to show restraint and tolerance during this critical period."