All five had crossed into Kyrgyzstan after Uzbek government troops moved to violently reassert control over the eastern city of Andijon.
Four of them -- Zhahongir Maqsudov, Yaqub Toshboev, Odilzhon Rahimov, and Rasulzhon Pirmatov -- were arrested in June 2005, despite having been granted refugee status by the UNHCR.
The fifth deportee, Fayoz Tojihalilov, was arrested in September and had been recognized as an asylum seeker by the UN.
Talking to RFE/RL's Uzbek Service from Geneva today, UNHCR spokeswoman Helene Caux described the decision to send them back to Uzbekistan as "a violation of international laws," including the 1951 international convention relating to the status of refugees.
"We're basically shocked by this extradition, which happened today," Caux said. "This is a [great] failure for the Kyrgyz government. We had been working for the past year to try to resettle these four refugees and this asylum seeker. We were thinking it would be possible, but Kyrgyzstan has decided otherwise."
Tursunbek Akun, the chairman of the Kyrgyz presidential human rights commission, also condemned the decision, calling it a "shame."
Other Kyrgyz rights activists expressed similar criticism. They fear the five deportees may be executed or tortured in Uzbekistan.