Kolesnikova has had no direct contact with the outside world for over a year. She has been prevented from receiving or writing letters, and is being held in constant isolation.
"The information we receive about Maria Kolesnikova from fellow prisoners is alarming. She now weighs only 45 kilos, is starving and is being held in constant isolation under dreadful conditions," writes the Belarusian exiled opposition leader Svetlana Tichanovskaja on X.
Maria Kolesnikova was one of the leaders of the historic demonstrations in 2020 against Belarus' dictator Alexander Lukashenko. She refused to leave the country but was eventually arrested, accused of crimes against national security and conspiracy to seize power.
Kolesnikova has been sentenced to eleven years in prison and is sitting in a penal colony, near the border between Russia and Ukraine.