"The ambassador of the United States is conspiring against democracy and wants Bolivia to break apart," said Morales, who is a fierce critic of US policy.
The government has blamed the unrest on the leaders of four states who demand greater autonomy and energy revenue and oppose Morales' plans to change the constitution and distribute land to the poor.
|Protests have erupted in several
regions of Bolivia [Reuters]
"What started out as a violent attack against the state is becoming a violent internal conflict fomented by the regional governors ... of several regions," said Ruben Gamarra, the interior minister.
At least two people were killed and a dozen people wounded in violent clashes between pro- and anti-government protesters in the northeastern town of Cobija, officials said.
Clashes broke out between armed pro- and anti-government supporters in the Amazon region of Pando while opponents of Morales occupied government buildings in the opposition stronghold of Santa Cruz.
Clashes also erupted in Tarija, a region rich in natural gas.
Bolivian radio said up to nine people may have been killed and five wounded in clashes between opponents and supporters of the government.
Morales, opening a public works project in La Paz, said: "We are going to be patient and cautious. We are going to hang in there. But patience has its limits, really."
Last week, Goldberg met Ruben Costas, the governor of Santa Cruz, Bolivia's richest province and the centre of a pro-autonomy revolt against the government.
South America's poorest nation has been in the grip of political turmoil for months.
Last month, Morales convincingly won a referendum on his rule but in the rebel states, voters also returned most of the governors forming the opposition coalition.
After failed negotiations to find a compromise solution, Morales announced a new referendum, to take place in December, to vote on his rewritten constitution, which would redistribute land and national revenues to give more to the indigenous population.