ALMATY, July 22 (Reuters) - Uzbekistan said on Thursday there was no legal basis for accepting a U.S. request to temporarily house thousands of Afghans while they await U.S. immigrant visas after having worked for American forces now pulling out of the country. Washington has asked Uzbekistan, Kazakhstan and Tajikistan to house some 9,000 Afghans who now risk being targeted by Islamist Taliban militants for cooperating with Western forces, according to a Bloomberg report this month. Insecurity has been growing in Afghanistan in recent weeks, largely spurred by fighting in its provinces as U.S.-led foreign troops complete their withdrawal and the Taliban launch major offensives, seizing districts and border crossings. read more Kazakhstan and Tajikistan have so far declined to comment on the U.S. request, and Ismatilla Ergashev, Uzbek President Shavkat Mirziyoyev"s special envoy on Afghanistan, became the first Central Asian official to openly discuss it. "This is a very serious and sensitive issue for Uzbekistan that cannot be decided immediately," Ergashev told local news website Kun.uz in an interview. Ergashev said Uzbekistan had not signed a 1951 convention relating to the status of refugees while its own laws had no provisions for granting anyone refugee status. "Therefore, taking into account external and domestic factors, there are no legal or practical grounds to provide asylum on our territory for Afghan citizens who cooperated with the United States," he said. He further said Taliban leaders had promised clemency to such Afghans and added that Tashkent was open to the idea of allowing the U.N. High Commissioner for Refugees to set up a representative office close to the Uzbek-Afghan border.