Venezuelan President Hugo Chavez is expelling the US envoy to Caracas, amid an escalating regional diplomatic row.
Mr Chavez said US ambassador Patrick Duddy had 72 hours to leave, adding the move was in solidarity with Bolivia.
It came just hours after Washington ordered out the Bolivian ambassador, in response to its own envoy being told to leave Bolivia.
Bolivia accuses the US envoy of inciting growing violent protests against President Evo Morales.
At least eight people were killed and some 20 injured in clashes between pro- and anti-government groups in Bolivia on Thursday.
Bolivia has seen large numbers of protests in recent weeks by opponents of Mr Morales's economic and social policies.
'Go to hell'
President Chavez used coarse language to describe his feelings about Washington as he ordered the expulsion of US envoy Patrick Duddy.
"The Yankee ambassador to Caracas has 72 hours to leave Venezuela, in solidarity with Bolivia, with the Bolivian people, and with the Bolivian government," Mr Chavez said.
"Go to hell 100 times," he said.
Mr Chavez also announced that he was recalling his envoy from Washington.
Earlier, the US state department declared that the Bolivian ambassador in Washington, Gustavo Guzman, was "persona non grata".
State department spokesman Sean McCormack said the decision was taken "in response to unwarranted actions, and in accordance with the Vienna Convention [on diplomatic protocol]".
He referred to Wednesday's move by Bolivia to expel US ambassador Philip Goldberg.
President Morales accused Mr Goldberg of "conspiring against democracy" and encouraging the break-up of Bolivia, but Mr McCormack said the expulsion was a "grave error", describing the accusations as "baseless".
The eight deaths in Bolivia's remote northern jungle region of Pando happened as pro- and anti-government protesters fought each other with clubs, machetes and firearms, officials said.
Seven of the victims were farmers killed by opposition activists, reports say.
A government spokesman described the killings as a massacre.
Protesters have also been blocking roads and occupying buildings in eastern regions, which are home to Bolivia's important natural gas reserves.
Opposition groups want greater autonomy as well as more control over revenues of natural gas in their areas.
They object to Mr Morales's plans to give more power to the country's indigenous and poor communities, by carrying out land reform and redistributing gas revenues.
On Monday, the government announced it was sending the military to protect gas fields and infrastructure from demonstrators and guarantee exports to neighbouring countries.
On Wednesday, officials said saboteurs had caused a blast on a pipeline, forcing them to cut natural gas exports to neighbouring Brazil by 10%.
The Brazilian foreign ministry said in a statement that the government was taking the necessary measures to guarantee gas supplies in the country.
The statement also expressed Brazil's "grave concern" at the events in Bolivia, and deplored the outbreak of violence and attacks on state institutions and public order.