Japan has issued an entry visa to exiled Uighur leader Rebiya Kadeer despite a Chinese request not to do so, sources said Friday.

Kadeer is scheduled to arrive in Japan on Sunday to attend the World Uighur Congress' general assembly, the sources said.

Her arrival will coincide with Prime Minister Yoshihiko Noda's appearance at a trilateral meeting with Chinese Premier Wen Jiabao and South Korean President Lee Myung Bak in Beijing.

China has called on Japan and other countries not to support Kadeer's "anti-China separatist activities." Her entry to Japan may irritate Beijing, which asked Tokyo through diplomatic channels to refrain from issuing the visa.

"Based on Japan's law, we just carried out the (visa) issuance procedure," a senior government official said on condition of anonymity.

Kadeer, the president of the congress, is living in exile in the United States but also visited Japan in 2009.

To attend the general assembly, which will begin in Tokyo next Monday, she applied for an entry visa about a month ago at a Japanese diplomatic establishment in the United States, the sources said.