Bolivian President Evo Morales, has rushed security forces to protect oil and gas pipelines that export energy from rebellious eastern lowland provinces, where violent protests over the control of Bolivia's energy reserves threatens to split the nation in two.
A threat by supporters of autonomy in the east to cut off natural-gas supplies to neighbors Brazil and Argentina has brought the potential conflict to a head.
Eastern militant groups demanding a share of recently nationalized energy reserves, seized an important gas-pumping station in the town of Yacuiba last week.
The seizure followed calls from the governors of Bolivia's four eastern provinces - Santa Cruz, Tarija, Beni and Pando - for greater self-rule and increased revenue from energy exports.
Mr. Morales responded by airlifting more than 1,000 elite security forces to guard a gas pipeline network that runs from the eastern provinces of Santa Cruz and Tarija, into neighboring Brazil and Argentina.
The response led to an uneasy standoff between local, pro-autonomy militants surrounding six major valve stations and national security forces - the latest escalation in regional tension that have plagued Bolivia since Mr. Morales took power in 2006.
Brazilian Foreign Minister Celso Amorim warned last week that his government was seriously monitoring the conflict in Bolivia and the possible disruption of a gas pipeline supplying 75 percent of energy needs to Brazil's largest city and business capital, Sao Paolo.
"We are analyzing how the Bolivian government can guarantee the integrity of the pipeline network," said Mr. Amorim, who stated that his government was prepared to "open direct contacts with eastern governors if necessary."
Bolivia faces a stark ethnic divide between its eastern population with some European ancestry and its Indian population of the western Andean highlands.
Mr. Morales, the nation's first Indian president, was elected on a platform to nationalize key industries and redistribute wealth to the nation's impoverished Indian population.
Anti-Morales demonstrators have formed a regional coordinating body in the east known by the Spanish acronym CONALDE, which also ordered takeovers of government installations and road blockades.
Regional and ethnic fault lines cracked open last month when Mr. Morales called for a national referendum on a new constitution that would place the eastern lowlands and its natural resources under state control.
Demographics suggest that the proposed charter would likely win a national vote.
Mr. Morales scored a 67 percent majority in a referendum on his rule last month.
The results were inverted, however, in the eastern provinces, which defied the government by approving "autonomous statutes" with almost 80 percent of the regional vote in local referendums held in June and July.
Militancy in the east is increasingly laced with racist rhetoric against Andean Indians.
Local "youth unions" have brought commerce and transport to a virtual standstill by blocking road connections between the eastern interior and the Andean capital of La Paz.
Supporters of Mr. Morales and his government were beaten and humiliated on the streets, and homes of officials were firebombed in several eastern cities and towns last week as militant youths took over customs and immigration offices at most border crossings with Brazil and Argentina.
Soldiers guarding tax offices in Beni were shot in the legs at close range by an armed group led by a locally born ex-military officer, who gave the garrison commander an "ultimatum" to withdraw his troops.
The national police chief in Santa Cruz, Col. Wilfredo Obleas, was assaulted and beaten by club-wielding youths after he fought attempts to take over his headquarters.
An attempt by national police to land reinforcements in Pando was aborted when local protesters burst into the forces' C130 airplane, took the commander hostage and forced his men to flee into the surrounding countryside.
Riot gear and weapons were confiscated by the local "civic committee."
Returning from a weeklong visit to Libya and Iran Friday, Mr. Morales called the violence a "civic coup" and vowed to restore order.
At this point, the standoff between Mr. Morales' national government resembles a civil insurrection more than a civil war.
Mr. Morales accused the Bolivian army of "genocide" for shooting protesters in 2003 - a charge that helped bring him to national prominence.
As a result, there is reluctance in the army and national government to use excessive force, even when anti-government demonstrations turn violent.
"There are two Bolivias now," Damian Caguara, a pro-Morales lawmaker recently told the London Guardian. "The Bolivia of the traditional, conservative, right-wing governments and the peasant one, the poor one, the indigenous one that has been in a state of submission for years.
"The latter is the one that is now running the [national] political scene, and this is provoking a harsh reaction from the bosses that cannot stand their servants, the Indians, to be ruling. For them, this is simply humiliating."
Indian supporters in La Paz and his home constituency of Cochabamba publicly called on Mr. Morales to impose military rule on the east by "declaring a state of siege before things get worse."
Mr. Morales has thus far committed the bulk of Bolivia's professionally trained elite units to guard the gas pipeline network from Santa Cruz and Tarija, where pro-autonomy militants have surrounded six major valve stations.
Helicopters sent by President Hugo Chavez of Venezuela were used to airlift more than 1,000 troops to key points along the pipeline network.