Serhiy Zhadan said on February 11 that he was in Minsk to attend a poetry festival but was ordered to leave on the basis of a 2015 Russian entry ban that accused him of "involvement in terrorism."
Zhadan said police and Belarusian KGB agents entered his hotel room while he was sleeping at about 2 a.m. on February 11 and took him into custody.
Zhadan, an acclaimed novelist and poet whose books have been widely translated, said nothing was explained to him initially by the authorities who detained him.
He said he was taken to a jail in Minsk, where he spent the rest of the night in a cell.
Writing on Facebook, Zhadan said: "It turns out that back in 2015 they banned me from entering Russia...for 'involvement in terrorist activity'."
Zhadan took part in pro-European protests in Kyiv that led to the ouster of Ukraine's Moscow-backed president in 2014.
In addition to the 2015 travel ban imposed against him by Russia, Zhadan had been targeted and assaulted by pro-Russia activists during the 2014 Maidan protests in Kyiv.
Iryna Herashchenko, first deputy speaker of Ukraine's parliament, told RFE/RL’s Belarus Service on February 11 that Russia created a special list of banned Ukrainian politicians and activists in an attempt to influence relations between Minsk and Kyiv.
"Russia's FSB (Federal Security Service) is behind this,' Herashchenko said. "There is a blacklist in which there are hundreds of Ukrainian politicians, activists, and public figures."
She said Russia's FSB should not be in a position to be able to decide which Ukrainians can and cannot visit Belarus.
Belarusian media published a photograph of Zhadan holding his passport with a stamp saying he is banned from entering Belarus.
That stamp does not include an expiry date for the ban.
The 42-year-old Zhadan lives in Kharkiv in the Kyiv-controlled part of eastern Ukraine.
He grew up in the Luhansk region that is now partly controlled by Russia-backed separatists and has openly supported Ukrainian government forces that are battling those separatists.
His support for Ukrainian government forces has included visits to the conflict zone and the raising of funds to help those living in the war-torn area.
His novels have won numerous European prizes.
In 2014, The New Yorker magazine called him "Ukraine's most famous counterculture writer."