By MATTHEW LEE

The Bush administration is facing a new headache, this time in Latin America, as two leftist governments it can't ignore booted the U.S. ambassadors this week.

Simmering ideological tensions between President Bush and the populist presidents of Bolivia and Venezuela boiled over on Wednesday and Thursday in twin diplomatic spats that threaten U.S. counternarcotics operations in the region and possibly American energy supplies.

The administration says it wants to get along with the growing number of leftist leaders in the Western Hemisphere, but Bolivian President Evo Morales and Venezuelan President Hugo Chavez are having none of it, essentially responding with the time-honored insult: "Yankee, go home."

Having chafed under U.S. pressure for reform and criticism of their unabashed fondness for arch-U.S. foe Fidel Castro, Morales and Chavez unloaded a torrent of anti-Bush rhetoric and suggested they won't restore normal ties with Washington until a new administration takes over.

Perhaps encouraged by his mentor Chavez, who famously described Bush as the devil at the United Nations and has cultivated relations with U.S. antagonists in Cuba as well as Iran and more recently Russia, Morales on Wednesday expelled U.S. Ambassador Philip Goldberg.

Morales, the former head of Bolivia's coca growers union, accused Goldberg of conspiring to oust him with Bolivia's conservative opposition, which is spearheading protests against his plans to redo the constitution and redirect natural gas revenues to the indigenous peoples.

"Without fear of the empire, I declare the U.S. ambassador 'persona non grata,'" Morales said in a speech at the presidential palace." "We don't want separatists, divisionists."

Washington called the allegations "baseless" and warned Thursday that the expulsion was a "grave error" that would badly damage U.S.-Bolivian ties. The State Department then declared Bolivia's top envoy to the United States, Gustavo Guzman, "persona non grata."

The situation deteriorated late Thursday when Chavez, who claims the Bush administration was behind a failed 2002 coup against him, followed suit, ordering U.S. Ambassador to Venezuela Patrick Duddy out of the country and recalling Venezuela's envoy to the United States.

"They're trying to do here what they were doing in Bolivia," Chavez told a crowd during a televised rally, accusing Washington, which he also refers to as "the empire," of again trying to oust him. "That's enough s... from you, Yankees," he said, using a barnyard expletive.

U.S. officials in Washington and Caracas said they had received no formal notice of the step and declined to comment on how they would respond, especially since Chavez appeared to have beaten them to the reciprocal punch by recalling his ambassador before he could be expelled.

The escalating spats could prompt similar moves from others in the region, notably that of former Sandinista leader and current Nicaraguan President Daniel Ortega, to act in solidarity, throwing a wrench into U.S. policy and further dimming its influence in Latin America.

Yet, Washington has its hands full already with the increasingly emboldened Morales and Chavez and other problems in the region.

Despite having pumped billions of dollars into anti-drug programs in the Andes, the administration has little show for it, with the possible exception of Colombia where a conservative leader has bucked regional trends and supports Bush.

Bolivia, the world's third-largest coca producer after Colombia and Peru, is key to U.S. counternarcotics efforts. It is also a major natural gas supplier to its neighbors, notably Brazil, whose leftist leader has taken a more moderate approach in his differences with Bush.

Venezuela, meanwhile, is the fourth-largest oil supplier to the United States, and in his speech Thursday Chavez threatened to cut off those crude shipments "if there's any aggression against Venezuela."