The Xinjiang regional government said Tuesday it has "solid evidence" that the separatist group World Uyghur Congress (WUC) led by Rebiya Kadeer masterminded Sunday's deadly violence in Urumqi.

Xinjiang police said they have obtained recordings of calls between overseas "Eastern Turkestan" groups and accomplices inside the country, Xinhua reported.

In the recorded calls, Kadeer reportedly said: "Something will happen in Urumqi." She also allegedly called her younger brother in Urumqi, saying, "We know a lot of things have happened." Authorities said the second call is in reference to the June 26 brawl involving workers from Xinjiang in a toy factory in Guangdong province, according to the report.

Anti-terror and regional experts said the WUC is connected with the World Uyghur Youth Congress - seen as one of the most-wanted terrorist groups by the Ministry of Public Security. They said the connection has enabled the WUC to wield significant influence in the region, which had fallen victim to several separatist attacks in the last two decades.

China has condemned the WUC to be a separatist organization, even though the organization has said its intention is for "peace and freedom for the Uygur community" since the group's establishment in 2004.

"The World Uyghur Congress has been advocating human rights and campaigns for so-called peace to hide its separatist attempts," said Xu Jianying, a researcher in border studies at the Chinese Academy of Social Sciences.

On Monday, Kadeer invited reporters to a news conference in Washington D.C. to refute her involvement in orchestrating riots between ethnic Uygurs and Han groups.

"The Chinese government always blames me and the World Uyghur Congress for problems over there," she said, adding the Chinese government is to blame for the deadly violence.

The Chinese government offered an immediate rebuttal.

"Anybody calling the violence a peaceful protest is trying to turn black into white in an attempt to mislead the public," Foreign Ministry spokesman Qin Gang said at a press conference Tuesday.

A Chinese court sentenced Kadeer, a 59-year-old former business tycoon from Xinjiang, to nine years in prison on charges of instigating and engaging in secessionist activities in 1999. But she was allowed to go to the US for medical treatment in March 2005 after promising to keep away from any separatist activities.

She then resided near Washington D.C. before becoming the president of the WUC.

Despite China's protest, she was nominated in 2006 as one of the candidates for the Nobel Peace Prize.

"Judging from what Rebiya Kadeer, leader of the WUC, had said and done, it is fair to say the organization masterminded the incident," Li Wei, director of the Center for Counter-Terrorism Studies with the China Institutes of Contemporary International Relations, told Xinhua Tuesday.

After the March 14 riot in Tibet last year, Kadeer reportedly said in public that something similar should happen in Xinjiang. The riot in Urumqi bore some similarities with the March 14 incident, Li added.

"The riot was by no means incidental and spontaneous," he said. "It was well organized, targeting civilians, and occurred simultaneously at several locations."

This year marks the 60th anniversary of the founding of the People's Republic of China, Li said. "The World Uyghur Congress has chosen this specific time."

Internet cut

Internet was cut in parts of Xinjiang's capital Urumqi following Sunday's deadly riot to prevent violence from spreading, an official said Tuesday.

"We cut Internet connection in some areas of Urumqi in order to quell the riot quickly and prevent violence from spreading to other places," said Li Zhi, the Communist Party of China (CPC) chief of Urumqi.

He didn't say when exactly Internet connections would resume.