Venezuelan President Hugo Chavez warned of a US-backed plot to topple his close ally, Bolivian leader Evo Morales.
The US government "is not going to give Evo a honeymoon. A destabilising plan is already under way to impede Evo from governing," Chavez said in a televised speech on Monday.
"First to impede him from governing so that the Bolivian people will become disenchanted," Chavez said. "And later, to topple him."
The Venezuelan leader has suggested previously that Washington was linked to moves to undermine the government of Morales, accusing it of having a hand in hotel bombings and protests earlier this year.
Meanwhile, Morales claimed in May that the United States was plotting to assassinate him.
US officials have denied that they are planning coups or assassinations against either Chavez or Morales.
Chavez said the US government was orchestrating the alleged plot. Referring to recent rumours about such an attempt, he said, "It's not the Bolivian opposition speaking, it's the US empire speaking."
Bolivia faced violent clashes between rival groups of miners last week and earlier strikes in several states across the country, and Chavez called that recent unrest part of a conspiracy against Morales.
Chavez said the US government has used the fight against cocaine trafficking to increase its military presence on the continent and accused it of seeking an "excuse" to overthrow Morales, who is pushing to decriminalise the coca plant, the main ingredient in cocaine.