Phnom Penh, Dec 20 - The Cambodian government deported 20 Uighur asylum seekers to China on the eve of the Chinese vice president's arrival in Phnom Penh on a state visit Sunday, drawing immediate criticism from the UN.

The 20 Chinese Muslims, who arrived in Cambodia last month from the far western Xinjiang region, were deported to China Saturday night, officials confirmed.

"Those refugees came to Cambodia illegally so they had to be sent back to their country," Interior Ministry spokesman Khieu Sopheak said.

Chinese Vice President Xi Jinping was scheduled to arrive in Phnom Penh Sunday.

"It is very clear that sending back those 20 Uighurs was planned just one day before the arrival of the deputy Chinese president's visit to Cambodia today," said Christophe Pescoux, Cambodia representative of the UN Office of the High Commissioner for Human Rights (UNHCR).

"We are greatly disappointed with this because Cambodia has signed the International Refugee Convention so they are supposed to protect refugees under this law," Pescoux said.

The Uighurs from Xinjiang, the site of violent anti-Chinese protests in July, entered Cambodia last month and were given "people of concern" status by the UNHCR before they were taken into police custody for violating immigration laws.

Earlier reports said 22 Uighurs, including three children, arrived in Cambodia overland, but Koy Kuong, spokesman for Cambodia's foreign affairs ministry, said authorities had only taken 20 into custody and have no knowledge of the two others.

"All 20 illegally entered Cambodia because they have no immigration papers, no visa," Koy Kuong said. "Therefore, they violated Cambodia's 1994 immigration law. They have to be deported because they are illegal immigrants."

Human rights groups said they feared the Uighurs would be mistreated in China.

The Uighur American Association said some in the group had witnessed security forces killing and beating Uighur demonstrators and they could face persecution, including possible execution, in China.

Clashes over the summer between Han Chinese and Muslim Uighur residents in Urumqi, Xinjiang's capital, left 197 people dead, according to Chinese government figures. However, Uighur exile groups said up to 800 people died, many of them Uighurs shot or beaten to death by police. (dpa)