The United States believes North Korea may be hiding more nuclear sites with potential military uses after revealing its construction of a uranium enrichment facility. U.S. envoy to the International Atomic Energy Agency Glyn Davies said, there is a clear likelihood that North Korea has built other uranium enrichment-related facilities in its territory. Speaking at a meeting of the IAEA's Board of Governors in Vienna on Thursday, Davies said, Washington believes North Korea began pursuing uranium enrichment long before April 2009, when Pyongyang claims its latest project started. North Korea said earlier this week that it has an enrichment facility with thousands of working centrifuges capable of producing fuel for a light water reactor currently under construction. Enrichment also could give North Korea an alternative means to produce nuclear weapons in addition to its known plutonium-based weapons program. IAEA Chief Yukiya Amano expressed great concern about North Korea's new nuclear facilities. His agency has been unable to verify North Korea's nuclear program since that state expelled U.N. inspectors last year and prevented the agency from engaging in full monitoring activities in 2002. China has appealed for easing tension and holding dialogue. It has urged the US, South Korea, Japan and Russia to attend emergency talks with North Korea in Beijing aimed at easing regional tensions. The US, South Korea and Japan have expressed reluctance to talks with North Korea at the present time, fearing that would reward Pyongyang for what they call provocative behavior.