Court spokeswoman Yulia Lyaskova told RFE/RL on February 12 that the trial of Pavlo Sharoyko is being held behind closed doors.
'We cannot comment when exactly the trial started and who is the judge as the trial is closed for outsiders,' Lyaskova said.
Lyaskova's comment came hours after Sharoyko's lawyer, Larysa Bykava, said that her client had gone on trial.
Sharoyko was detained in Belarus in November.
Ukraine and Belarus expelled each other's diplomats after Sharoyko's arrest.
Sharoyko's colleagues said at the time that he had been working on stories related to the search for Pavlo Hryb, a 19-year-old Ukrainian citizen who disappeared in Belarus after being arrested and was later found to have been sent to Russia, where he was charged with terrorism-related offences.
Relations between Russia, Belarus, and Ukraine -- mostly Slavic former Soviet republics with deep historical and cultural ties -- have been strained since Moscow seized control of Ukraine's Crimea region and threw its support behind armed separatists in eastern Ukraine in 2014.