Bolivia's leftist president Evo Morales on Saturday accused US intelligence of hacking into the email accounts of top Bolivian officials, saying he had shut his own account down.
Latin American leaders have lashed out at Washington over recent revelations of vast surveillance programs, some of which allegedly targeted regional allies and adversaries alike.
Bolivia has joined Venezuela and Nicaragua in offering asylum to Edward Snowden, the former IT contractor for the US National Security Agency who publicized details of the programs and is now on the run from espionage charges.
Morales said that he learned about the alleged US email snooping at the Mercosur regional summit in Montevideo earlier this week.
"Those US intelligence agents have accessed the emails of our most senior authorities in Bolivia, Morales said in a speech.
"It was recommended to me that I not use email, and I've followed suit and shut it down," he said.
Argentine Foreign Minister Hector Timerman told the same summit that more than 100 of his country's officials were under electronic surveillance from a nation he did not name.
Bolivia's Morales, who has long had a thorny relationship with the United States, speculated that Washington hoped to use the information in the emails to plan a future "invasion" of his country.
His allegations followed a diplomatic dust-up last week when, during a flight home from Moscow, European authorties diverted Morales's plane to Austria and searched it after rumours that he had Snowden on board.
Morales renewed his offer of asylum to Snowden on Saturday, saying La Paz would follow all "diplomatic norms and international accords" in the case.
The 30-year-old intelligence leaker has been stranded in an airport transit zone in the Russian capital since June 23.
Snowden is seeking to avoid US espionage charges for revealing vast surveillance programs to collect phone and Internet data.
US authorities say the revelations threatened national security, insisting the secret programs are fully legal and have helped foil dozens of terrorist attacks.