Jailed Belarusian opposition leader Maria Kolesnikova, who was admitted to intensive care last week, has been returned to jail and is being monitored by doctors, her allies have said.She was arrested and handed 11 years behind bars last year in the wake of huge and long-running popular protests against the authoritarian rule of strongman Alexander Lukashenko."Maria was transferred from the Gomel emergency hospital to her penal colony over the weekend," a statement from the press service of fellow opposition politician Viktor Babaryko said Monday.Fears rose after news that Kolesnikova, one of the leaders of historic demonstrations against Belarusian strongman Alexander Lukashenko, had been admitted to a medical facility for treatment.The statement said that Kolesnikova will be monitored by doctors for at least 10 days.Kolesnikova's father "managed to see his daughter and confirmed that she is alive" during a 10-minute visit, the statement said."She lost some weight and still has little strength," Babaryko's press service said, adding that she had received treatment for a perforated ulcer.On Thursday last week her allies reported she was "getting better."The 40-year-old was part of a trio of women along with Veronika Tsepkalo and Svetlana Tikhanovskaya who spearheaded massive rallies that broke out across Belarus against Lukashenko in 2020.She refused to go into exile and tore up her passport but was ultimately jailed for violating national security and conspiring to seize power.Lukashenko violently dispersed demonstrations in 2020, detained thousands of protesters and forced into exile or jailed critical activists and journalists.Both Tikhanovskaya and Tsepkalo live in exile.