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The chief of Bolivia's (search) armed forces warned Thursday that the military could intervene in a grave political crisis as lawmakers gathered to name a new president. Meanwhile, the near month-long crisis reportedly claimed its first life when a protesting miner was killed in the country's south.

Navy Adm. Luis Aranda Granados (search) went on national television to urge the lawmakers to remain within the bounds of the constitution and hear the "will of the people" in their work to choose a new leader. But he rejected an assessment by outgoing President Carlos Mesa (search) that the country was on the brink of a civil war.

"It's evident that there does exist a risk of confrontation between Bolivians, but I would say the term 'civil war' is too extreme," Granados said. "Confrontation between Bolivians is the greatest risk."

In Bolivia's tightly guarded historic capital of Sucre (search), the lawmakers were to open an emergency session of Congress to name a replacement for the U.S.-backed Mesa, who resigned Monday after weeks of violent street protests.

They were widely expected to name Senate leader Hormando Vaca Diez (search), a conservative lawyer and landowner who is next in line to assume the presidency. The protesters have vowed to drive Vaca Diez from office if he assumes the presidency.

"We are going to respect the decisions of Congress because we are making a serene call for all actors in this conflict ... to arrive at a real solution," Granados said. "As long as there is no break in the constitutional and democratic system, we will continue to safeguard this entire process."

Moments after the admiral's comments, Vaca Diez announced the postponement of the congressional session so party leaders could meet.

"We are right now entering into our party meetings," Vaca Diez said without elaborating.

Street protests by indigenous groups, miners, students, labor activists and farmers have crippled Bolivia since May 14. The demonstrators, often numbering in the tens of thousands, have marched almost daily in the paralyzed capital of La Paz, demanding more social benefits for the poor and such steps as nationalizing Bolivia's oil industry.

A group of protesting miners said their leader was killed in a confrontation with soldiers, which if confirmed by authorities would be the first death of the crisis. Miners told an Associated Press photographer that they were stopped by soldiers while traveling in trucks toward Sucre and gunfire erupted, leaving the union official dead. They gave no further details.

The body was photographed covered with a sheet moments before it was taken away by ambulance about 25 miles outside Sucre. The miners said one other miner was wounded but authorities had no confirmation of the account.

The protesters are demanding that Vaca Diez and the next-in-line to succeed Mesa both step down to allow the Supreme Court chief justice to take power and call early elections.

Leftist opposition leader Evo Morales lashed out late Wednesday at Vaca Diez, saying he was a wealthy landowner and another discredited member of the "mafia of the oligarchy" that has ruled Bolivia for decades.

"We will wage a campaign of civil disobedience" against any Vaca Diez presidency, warned Morales, a leader of poor coca leaf-farmers and a House deputy who heads a leftist party, the Movement Toward Socialism. "The street mobilizations will not halt."

La Paz Mayor Juan Del Granado also stepped up pressure for early elections by announcing he and 20 other civic colleagues were beginning a hunger strike, adding, "Our protest is not about politics, but about the future of Bolivia."

A farmer and businessman, Vaca Diez, 56, hails from the eastern region of Santa Cruz and is widely seen as a conservative and free-market supporter. However, his MIR party has been mired in past corruption scandals and is reviled by Indian and labor groups in the western highlands around La Paz.

Morales and other leaders are trying to persuade Vaca Diez to immediately resign the presidency, giving it to second-in-line House leader Mario Cossio. They want Cossio to resign as well, sending the presidency to third-in-line Supreme Court Justice Eduardo Rodriguez.

If Rodriguez becomes president, he must call elections within five months, while either Vaca Diez or Cossio would be allowed by law to serve out Mesa's term, which runs until August 2007.

Vaca Diez refused Thursday to say whether he would allow such a scenario if elected.

"I hope that all goes well and that the peace can be restored in Bolivia," he said.

Camouflaged army troops with rifles at ready guarded the whitewashed hall where the leaders were to open their session in Sucre, the historic capital after Bolivia gained independence in the 19th century. Legislative and executive branches of government later relocated to La Paz, though the Supreme Court is still headquartered in Sucre.

Chronically unstable Bolivia, landlocked and with much of the country at high altitudes in the Andes Mountains, is South America's poorest nation. It is split between Indian and labor groups from the poor western highlands, and the ruling class from Santa Cruz in the east and the oil-rich gas fields to the south.

The divides created by the U.S.-backed war on drugs also are at issue: Opposition leader Evo Morales draws his support from farmers who grow coca leaf, the raw ingredient for cocaine, while Vaca Diez likely would ally himself with the U.S. campaign to eradicate coca leaf plantations.

Morales demanded congressional leaders call early elections in which the anti-U.S. leader would likely be a leading candidate, although he failed in one earlier bid for Bolivia's presidency.