Sept. 11 (Bloomberg) -- The U.S. expelled Bolivian Ambassador Gustavo Guzman today, a day after Bolivia's President Evo Morales ordered the U.S. ambassador out of La Paz amid charges that he supported regional leaders backing more autonomy.

``In response to the unwarranted action and in accordance with the Vienna Convention, we have officially informed the government of Bolivia of our decision to declare Ambassador Gustavo Guzman persona non grata,'' said U.S. State Department spokeswoman Heide Bronke.

Morales yesterday accused U.S. envoy Philip Goldberg of supporting opposition groups and said he was no longer welcome in Bolivia. The rupture may weaken U.S. support to renew trade preferences for Bolivian imports that expire at the end of this year and prompt Morales to rely more on Venezuelan President Hugo Chavez for economic and political support.

The fissure could also undermine U.S. efforts to reduce the cultivation of coca, the main ingredient in cocaine. The land- locked nation, South America's poorest country, is the third- biggest producer of coca after Colombia and Peru.

The U.S. imported $363 million worth of goods from Bolivia in 2007 and exported $278 million, according to the U.S. Department of Commerce. Bolivia's gross domestic product was about $13 billion last year, according to Bloomberg data.

The decision to expect Goldberg was ``a grave mistake on the part of President Morales'' said Thomas Shannon, the top U.S. diplomat for Latin America. U.S. Congressman Eliot Engel, chairman of the subcommittee responsible for Western Hemisphere affairs, said trade and aid ties with Bolivia should be reviewed.

Political Disputes

A message left at the press office of Bolivia's foreign affairs ministry wasn't immediately returned.

Morales's move came during a week of intensifying political disputes between his government and regional leaders opposed to a new constitution and Morales's control over energy tax revenue. Morales frequently charged Goldberg with conspiring with opposition groups, an accusation the State Department called ``baseless.''

A pipeline in the southern state of Tarija that carries natural gas was attacked and cut yesterday, disrupting supplies to Brazil, the biggest consumer of Bolivian gas. Bolivian officials blamed opposition groups. Clashes between protesters and police across much of the ``half moon'' region, as the country's eastern provinces are known, left as many as eight people dead, EFE reported.

``We won't tolerate the separatism that has divided other countries,'' Morales, 48, said in a speech in La Paz today.

Morales, like Chavez, calls the U.S. ``the empire'' and last year said the United Nations headquarters should be moved out of the country.

Venezuelan Support

``If they overthrow Evo, if they kill him, let the Bolivian coup mongers know that they'll be giving me a green light to support any armed movement in Bolivia,'' Chavez said today in comments broadcast by state television.

Bolivia has the second-biggest natural gas reserves in South America after Venezuela, producing about 32 million cubic meters of gas per day. Brazilian Mines and Energy Minister Edison Lobao said Bolivia's daily gas supply to Brazil is 3 million cubic meters short of normal levels.

``The most effective way to bring this country to its knees is to shut the pipelines,'' said Carlos Alberto Lopez, a former deputy minister of energy, in a phone interview from La Paz.

Jose Miguel Insulza, Secretary-General of the Organization of American States, said Sept. 10 that he was ``profoundly worried'' about growing violence in Bolivia.

New Constitution

After four of Bolivia's nine provinces approved referendums this year calling for greater autonomy from the central government, Morales backed a recall referendum on Aug. 10 that left both him and his main opponents, including Santa Cruz Governor Ruben Costas, in office. Afterwards, Morales promised a national vote on a new constitution in January.

The dispute between the central government and regional leaders has racial as well as economic overtones. The opposition, based in the eastern lowlands, draws more support from a wealthier, European-descended population than Morales, a western Bolivian of indigenous Aymara descent who took office in 2006.

``Both sides are entrenched in this dispute,'' said Lopez. ``There's so much tension and repressed aggression in Bolivia right now.''

To contact the reporter on this story: Viola Gienger in Washington at vgienger@bloomberg.net; Bill Faries in Buenos Aires at wfaries@bloomberg.net

Last Updated: September 11, 2008 18:59 EDT