"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," State Department spokesman Sean McCormack said.
It was unclear exactly how long 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 earlier Thursday and told of the decision a day after Bolivia expelled U.S. Ambassador Philip Goldberg, officials said.
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.
In La Paz, Bolivian Foreign Minister David Choquehuanca told reporters that he formally had requested Goldberg's expulsion but added that he also wrote Secretary of State Condoleezza Rice to say Bolivia "wishes to maintain bilateral relations."
A share of U.S. aid to Bolivia goes to eastern provincial governments that are the nexus of opposition to Morales, which has angered the Bolivian president and his supporters.
Goldberg met last week with Ruben Costas, one of Morales' most virulent opponents. Costas is governor of Santa Cruz, Bolivia's richest province and the seat of a pro-autonomy revolt against the nation's first indigenous president.
The State Department also said the Morales government has asked Drug Enforcement Agency employees to leave a base camp in the coca-growing region of Chapare "because they could no longer protect them." State Department employees left too, the department said.
"We are disappointed that 25 years of working side by side with our counterparts at the Bolivian special counternarcotics police has been disrupted in this manner," the State Department said in a statement.
At least six people were killed as anti-government protesters fought backers of Morales on Thursday in Bolivia's pro-autonomy east with clubs, machetes and guns, police said.
Venezuela President Hugo Chavez said the U.S. ambassador has 72 hours to leave Venezuela and that he's recalling his ambassador from Washington.
Chavez said Thursday night that he is asking U.S. Ambassador Patrick Duddy to leave, in part, to show solidarity with Bolivian President Evo Morales, who expelled Washington's envoy in La Paz.
"They're trying to do here what they were doing in Bolivia," Chavez said.
"That's enough ... from you, Yankees," he said, using an expletive.
The socialist leader said Venezuela's ambassador to Washington, Bernardo Alvarez, would return to the U.S. "when there's a new government in the United States."
The move by Chavez brings relations with Washington to a new low and raises questions about whether the diplomatic clash could eventually hurt trade. Venezuela is a major oil supplier to the United States, which is the country's No. 1 client.
Chavez announced the decision during a televised speech, hours after saying his government had detained a group of alleged conspirators in a plot to overthrow him.
Chavez accused the group of current and former military officers of trying to assassinate him with backing from the United States. He didn't offer evidence.
U.S. officials have repeatedly denied Chavez's accusations that Washington has backed plots against him.
A U.S. Embassy spokeswoman didn't immediately return a call seeking comment.
Chavez warned last month that Duddy could soon be "packing his bags" after the diplomat lamented that U.S. and Venezuelan officials have not been cooperating in the war on drugs.
Duddy has said that deteriorating diplomatic relations between Caracas and Washington were giving drug smugglers the upper hand.