A Belarusian military expert and journalist, Alyaksandr Alesin, has been missing for days.
Media reports in Belarus on December 4 said thata that Alesin was arrested in a cafe in downtown Minsk last week on espionage charges.
Belarusian KGB spokesman Artur Strekh refused to comment to RFE/RL on the reports on December 5.
Alesin's colleagues at the newspaper "Belarusians & Market" told RFE/RL that he had been missing for several days, but gave no other details.
Alesin is a leading military expert whose comments often do not coincide with the government's positions in tightly controlled Belarus.
Alesin has said Belarus should reform and modernize its army in light of the situation in neighboring Ukraine, where separatists with Russian support have seized swaths of territory in a conflict that has killed more than 4,300 people.