The Sunday violence in Urumqi was "an evil killing, fire setting and looting", said Foreign Ministry spokesman Qin Gang on Tuesday.
"Anybody calling the violence a peaceful protest is trying to turn black into white in an attempt to mislead the public," Qin told a regular press conference.
More than 150 people died and a further 1,000-odd were injured in the riot Sunday evening in Urumqi, capital of northwest China's Xinjiang Uygur Autonomous Region.
Qin said this was an action born out of the fear of Xinjiang's social progress, solidification and prosperity.
"The violence is a pre-empted, organized violent crime. It is instigated and directed from abroad, and carried out by outlaws in the country," Qin said, noting that the evidence was irrefutable and conclusive.
Xinjiang police said Monday they had evidence that separatist World Uyghur Congress leader Rebiya Kadeer masterminded the riot.
Rebiya Kadeer, a former businesswoman in China, was detained in 1999 on charges of harming national security. She was released on bail on March 17, 2005 to seek medical treatment in the United States.
"Rebiya Kadeer is also involved in serious economic crime," Qin said, noting that the Chinese government, out of humanitarian consideration, allowed her to remain out of custody and obtain medical treatment, and she had promised not to engage in actions endangering the country's security before her departure.
A series of facts in recent years proved that she was totally a liar. She took separatist actions at all times when living abroad, Qin said, urging related countries to see clearly the essence of Eastern Turkestan groups, and not to extend sympathy or support to them in any form.
According to a local official, the Chinese authorities had evidence that Rebiya Kadeer used the Internet and other means of communication to mastermind the riot in Xinjiang.
Internet was cut in parts of Urumqi following the deadly riot to prevent violence from spreading.
Qin said this measure was taken in order to deal with the incident and safeguard local stability.
After the Sunday riot, The Xinjiang judicial department arrested some suspects in order to safeguard the normal life of the local people.
"What they have done was justified, and any country could take the same measures while facing this violence," Qin said.
He also said that China, by rule of law, would not wrong one innocent person, nor setting free any evil one.
Qin refuted the accusation by some human rights organizations criticizing Chinese government's measures to deal with Xinjiang violence.
"Those organizations view the case with bias, and their conclusion could not objectively undoubted and it stands in the opposite direction of ethics, laws and all Chinese people's minds," he said.
Foreign journalists, about 60 in number, were in Xinjiang on a reporting trip arranged by the Information Office of the State Council, the Chinese Cabinet.
"China takes an open and transparent principle on the news report and offer active help and convenience for the foreign and Chinese journalists to cover news in Xinjiang," Qin said.
A press center had been established in Urumqi, with service offered by officials there, Qin said, hoping that the media would fairly report the truth.
Qin also reminded the reporters to abide by related regulations and laws, and take care of their own security.