Presidential Minister Juan Ramon Quintana said Bolivia would "denounce before the entire world" that the United States had "participated in the massacare" Sept.
Quintana did not provide any evidence for the charge or elaborate on what he meant by the word "participate," alleging only that the United States "accompanied the criminal policies" of Pando's opposition governor, Leopoldo Fernandez, who has since been jailed for allegedly fomenting the violence.
Quintana also accused the U.S. Agency for International Development of unspecified "direct involvement" in the province.
U.S. officials could not be reached for comment Friday night.
Morales has frequently accused the United States and its aid programs of conspiring against his government. U.S. officials have denied the charges.
An already tense relationship between the two countries has soured dramatically in recent months. Bolivia booted its U.S. ambassador last month and Washington quickly followed suit.
The United States later placed Bolivia on an anti-narcotics blacklist after Morales supporters demanded U.S. aid programs and Drug Enforcement Administration officials leave a central Bolivian coca-growing region last month.
Washington has since announced the suspension of a trade deal.
Bolivia alleges U.S. role in violent clash
AP, October 24