The Bush administration has ordered Bolivia's ambassador to leave the United States after Bolivia expelled the US envoy there, the US 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 on Thursday.
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 yesterday and told of the decision a day after Bolivia expelled US 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 US-Bolivian relations.
A share of US 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.