Anti-government protesters fought backers of President Evo Morales on Thursday in Bolivia's pro-autonomy east with clubs, machetes and guns and seized more natural gas fields.

At least one person was killed and 20 injured in street fights, authorities reported.

Meanwhile, the Bush administration ordered Bolivia's ambassador on Thursday to leave the United States after Bolivia expelled the U.S. envoy there, the U.S. State Department said.

"In response to unwarranted actions, and in accordance with the Vienna Convention (on diplomatic protocol), we have officially informed the government of Bolivia of our decision to declare Ambassador Gustavo Guzman persona non grata," spokesman Sean McCormack said.

It was unclear exactly how quickly Guzman would have to leave the United States, but diplomats declared "persona non grata" are generally given 72 hours to depart. Guzman had been summoned to the department Thursday and told of the decision a day after Bolivia expelled U.S. Ambassador Philip Goldberg, officials said.

Bolivia said it told Secretary of State Condoleezza Rice it wants to maintain relations.

Bolivia's leftist President Evo Morales had ordered Goldberg out, accusing him of conspiring with Bolivia's conservative opposition.

McCormack earlier had called that a "grave error" and warned that Bolivia would face retaliatory actions for the expulsion, which he said had inflicted serious damage on U.S.-Bolivian relations.

Half of Bolivia's natural gas exports to Brazil — its No. 1 customer — were halted for nearly seven hours on Thursday because of sabotage by anti-Morales activists, according to the affected Transierra pipeline company.

Protesters also stormed the Pocitos gas installation that supplies neighboring Argentina. Plant technicians shut off gas to the country as a precautionary measure, an engineer at Pocitos told The Associated Press.

However, an executive with Transportadora Gas del Norte, the Argentine pipeline company that receives the Bolivian gas, told the AP that the gas flow was unaffected Thursday.

Both officials spoke on condition of anonymity, saying they were not authorized to comment on the matter.

Bolivia's finance minister, meanwhile, said gas deliveries to Brazil would be curtailed by 10 percent for up to two weeks as workers fix a pipeline ruptured by protesters on Wednesday. Bolivia supplies Brazil with 50 percent of its natural gas.

A two-week protest against Morales' plans to redo the constitution and redirect gas revenues turned violent this week as demonstrators in the country's energy-rich eastern provinces stormed public offices, blocked roads and seized gas fields.

Opposition groups in the provinces — Santa Cruz, Beni, Pando and Tarija — are fighting Morales' leftist government for control of Bolivia's lucrative gas revenues.

They also are demanding he cancel a Dec. 7 nationwide vote on a new constitution that would help him centralize power, run for a second consecutive term and transfer fallow terrain to landless peasants from Bolivia's poor indigenous majority.

"We're going to tolerate only so much. Patience has its limits," Morales told supporters on Thursday. The Aymara Indian and former coca growers' union leader has so far hesitated to mobilize the military, fearing major bloodshed.

Deputy Interior Minister Ruben Gamarra told reporters that a provincial official in Pando was killed Thursday in street violence between pro- and anti-government bands near the regional capital of Cobija.

Presidential spokeswoman Nancy Teixera said at least 20 people were injured. Radio reports said the groups fought with clubs, machetes and shotguns in the jungle region where many people hunt game. Interior Minister Alfredo Rada confirmed the use of firearms.

Gamarra said there were unconfirmed reports of three more deaths. He blamed opposition governors and civic leaders in the east for "continuing to incite the violence."

About 80 people were hurt in another clash late Wednesday in the natural gas-rich province of Tarija where the gas fields were seized, according to police and media reports.

The protests forced the closure of various regional airports, and American Airlines canceled all flights to Bolivia through Saturday. Company spokeswoman Martha Pantin said it expected flights to resume beginning Sunday.

In Washington, State Department officials said the Bush administration had ordered the expulsion of Bolivia's ambassador to the U.S. after Bolivia expelled the U.S. envoy there.

The officials said the Bolivian diplomat, Gustavo Guzman, was summoned to the department on Thursday and told he must leave the country. The officials spoke on condition of anonymity ahead of a formal announcement by the State Department.

Bolivia's leftist President Evo Morales had ordered Goldberg out, accusing him of conspiring with Bolivia's conservative opposition. State Department spokesman Sean McCormack called that a "grave error."

In Venezuela on Thursday, President Hugo Chavez threatened military intervention if his ally Morales were to be overthrown: "It would give us a green light to begin whatever operations are necessary to restore the people's power."