The US State Department said Friday it is trying to confirm with Beijing reports it has sentenced to death some of the 20 Uighurs who were deported from Cambodia in 2009.

"We are concerned that China has reportedly sentenced two of them to life in prison. We're seeking to confirm these reports with the Chinese," State Department spokeswoman Victoria Nuland told reporters.

Some media reports have said four were sentenced to death.

Washington "has repeatedly called on the Chinese government to provide information on the whereabouts of all 20 of the Uighur asylum seekers," Nuland added.

It has also asked Beijing "to allow access to them by international agencies and to treat them in accordance with international human rights obligations and commitments," Nuland said.

The deportees, members of the mainly Muslim minority Uighur group who have long complained of oppression in Xinjiang, fled China after ethnic rioting in the remote, northwestern region in 2009.

They applied for UN refugee status in Cambodia, but were forcibly repatriated to China in December 2009, in a move that triggered strong international condemnation.

Cambodia's decision to deport the Uighurs was quickly followed by a 1.2-billion-dollar aid and loan package from Beijing. China has rejected accusations of a link between the two.

According to the World Uyghur Congress, China has refused to confirm the whereabouts of members of the group despite media reports that four were sentenced to death after their return, while another 14 were jailed for life.

"Uighurs forcibly returned to China are in extreme risk of torture, detention and enforced disappearance," Rebiya Kadeer, president of the Munich-based exile group, said in a statement emailed to AFP.

"We call once again on international governments to pressure the Chinese authorities to immediately disclose the whereabouts of all the extradited Uighurs and to provide the charges, if any, that have been made against them."

China has said the Uighurs were wanted in connection with rioting that erupted in July 2009 in the regional capital of Urumqi between Uighurs and China's majority Han ethnic group which left nearly 200 people dead.