China on Tuesday rebutted US accusations that Beijing facilitated the flight of former US National Security Agency contractor Edward Snowden, saying the blame was "baseless and unacceptable".

Experts said Washington should not go further to let the event spill over and hamper overall ties.

Snowden, a fugitive who is wanted by the US government on charges of espionage, left Hong Kong for Moscow on Sunday.

The Hong Kong Special Administrative Region said in a statement that Snowden left voluntarily and that it had informed the US of the situation.

Foreign Ministry spokeswoman Hua Chunying said at a regular news conference that Hong Kong has handled the case completely according to its law.

"This is beyond dispute. All parties should respect this," Hua said.

"Washington has no reason to call into question the Hong Kong SAR government's handling of affairs according to the law.

"The US criticism of China's central government is baseless. China absolutely cannot accept it."

The remarks came after former US secretary of state Hillary Clinton lashed out at China in Los Angeles on Monday.

"That kind of action is not only detrimental to the US-China relationship, but it sets a bad precedent that could unravel the intricate international agreements about how countries respect the laws - and particularly the extradition treaties," the possible 2016 presidential contender said.

White House spokesman Jay Carney also criticized Beijing in unusually harsh language about Snowden's departure.

"This was a deliberate choice by the government to release a fugitive despite a valid arrest warrant," Carney said. He said China had "unquestionably" damaged its relationship with Washington.

"The Chinese have emphasized the importance of building mutual trust," Carney said. "We think that they have dealt that effort a serious setback. If we cannot count on them to honor their legal extradition obligations, then there is a problem."

However, Stephen Walt, an international affairs professor at Harvard University's John F. Kennedy School of Government, said on Twitter on Monday, "If Snowden were Chinese or Iranian, had leaked info about their spying and sought asylum in the US, we'd grant it and call him a hero."

The South China Morning Post in Hong Kong revealed on Sunday Snowden's new claims that the US has been hacking into Chinese mobile phone companies and a backbone network, to steal text messages and data of millions of Chinese citizens.

Chinese media and Internet users have demanded an explanation from Washington.

Shi Yinhong, an expert on US studies at Renmin University of China in Beijing, said Snowden's departure from Hong Kong might have been the best result for relations between Beijing and Washington.

Kenneth Lieberthal, a China expert at the Brookings Institution who was an Asia adviser in former US president Bill Clinton's government, told Reuters that linking Snowden to other issues would undo careful policy aimed at handling issues through separate channels to avoid big ruptures in ties.

"Over the years, we've sought to prevent any serious disagreement in one issue area from spilling over and degrading the entire relationship," he said.

Reuters contributed to this story.

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