PRAGUE, Nov 25 (Reuters) - Czech President Milos Zeman was taken back to hospital on Thursday after testing positive for the coronavirus, his office said, just hours after his release following more than six weeks of treatment for an unrelated condition. Zeman, 77, was released to home care on Thursday morning but an ambulance took him back to the Central Military Hospital (UVN) in the evening after testing positive at the presidential retreat at Lany, west of Prague. The hospitalisation means Zeman will not for the time being appoint centre-right opposition leader Petr Fiala as prime minister, which had been planned for Friday. "The president"s programme will be suspended pending the treatment of COVID-19," his office said in a statement. Zeman has been vaccinated against the coronavirus three times and local media quoted unnamed sources as saying he showed no symptoms. News website www.seznamzpravy.cz quoted UVN director Miroslav Zavoral, who is Zeman"s main physician, as saying he had the president, who had been receiving visits during his previous hospitalisation, take a test for COVID-19 after a "risky" contact with an employee at Lany. He was taken to the hospital to receive treatment with monoclonal antibodies, he said. The president was previously admitted to hospital on Oct. 10 with complications to a chronic illness that his office never specified but which doctors said was a liver condition. He went into hospital a day after a parliamentary election in which Zeman"s allies, led by Prime Minster Andrej Babis, lost to a centre-right coalition and the president"s leverage over parliament was undermined. Zeman was initially treated in an intensive care unit and doctors said the prognosis was uncertain. Parliament prepared to debate taking away his presidential duties but after several weeks the president"s condition improved. He had said he would respect the election result and that he would appoint the centre-right leader Fiala as prime minister on Friday, with the appointment of the Cabinet to follow later. The hospital said earlier that the president had decided to continue treatment at the presidential retreat despite suggestions from the hospital that he should stay. The hospital said Zeman, his family and closest colleagues had been informed about potential risks and complications and that it had recommended he be treated in a specialised medical facility. But it said there had been a "significant improvement" in Zeman"s condition and that it respected his decision to "give preference to performing his constitutional duties". Before his hospital stay, Zeman had tried to improve relations with Russia and China, but relations soured with Moscow in a spy row and with Beijing over failed investment plans. The incoming government intends to reinforce the country"s Western orientation and strengthen relations with democracies including Taiwan, which China claims as its territory. Zeman has 15 months remaining in his second and final five-year term.