Belarusian President Alexander Lukashenko said he had foiled a US-planned "coup" and "assassination" attempt against him and his family.
Lukashenko also said that two people have been arrested by Russian security forces in Moscow in relation with the operation: political scientist Alexander Feduta and lawyer Yuri Zenkovich, who also has US citizenship.
It comes after the Belarusian security services, the KGB, announced on Friday evening that they had dismantled, during a "special operation", an "organised group of terrorist orientation" which was planning the "physical elimination of the president and his family" and "the organisation of an armed rebellion in order to take power by violent means".
In a video released by the presidency, Lukashenko claimed that "we detained the group, they showed us how they had planned everything, I remained silent.
"Then we discovered the work of clearly foreign intelligence services, most likely the FBI, the CIA," he went on.
Neither Russia nor the US has commented on Lukashenko's assertions.
The Belarus strongman has been in power since 1994 and claimed a landslide victory in the 2020 presidential election ruled fraudulent by the opposition and Western countries.
Since then, mass protests against his rule have taken place regularly across the country despite the violent crackdown orchestrated by the authorities. The EU, UK and US have all imposed sanctions against high-ranking Belarusian officials over the election rigging and subsequent repression.
Belarusian opposition leader Svetlana Tikhanovskaya, who has taken refuge in Lithuania, denounced a "provocation by the Russian and Belarusian security services, in which citizens of Belarus and the United States were dragged in".
"It is necessary to refrain from making decisions and coming to hasty conclusions that could harm the national interests, sovereignty and independence of Belarus," she said, quoted by her press service.
Tikhanouskaya is to meet with the Us ambassador to Belarus next week.