Ashley Tellis, 64, who has worked in or advised the US government for more than two decades, was found to have kept more than 1,000 pages of top-secret or secret documents in his home, a criminal affidavit said.

Late in the evening of September 25, Tellis entered the State Department, where he served as an unpaid advisor, and appeared to print from a secret document on US Air Force techniques, the affidavit said.

It said Tellis met multiple times with Chinese government officials at a restaurant in the Washington suburb of Fairfax, Virginia.

At one dinner, Tellis entered with a manila envelope but did not appear to leave with it, and on two occasions the Chinese officials presented him a gift bag, the affidavit said.

Tellis faces up to 10 years in prison and a $250,000 fine if convicted on the charges of unlawfully holding documents, the Justice Department said.

"The charges as alleged in this case represent a grave risk to the safety and security of our citizens," said Lindsey Halligan, the US attorney for Virginia's eastern district who has become known for pursuing charges against critics of President Donald Trump.

The State Department confirmed that Tellis was arrested Saturday -- the same day the affidavit said he was due to fly to Rome -- but declined further comment due to the ongoing investigation.

Tellis, a naturalized US citizen originally from India, is a senior fellow at the Carnegie Endowment for International Peace and served in senior positions under former president George W. Bush.

He helped negotiate the Bush administration's civil nuclear deal with India that was seen as a landmark in building ties between the world's two largest democracies.

But in recent years, Tellis has become known as one of the most outspoken contrarians in Washington on the US courtship of India.

In a recent essay in Foreign Affairs, Tellis said India was often pursuing policies at odds with the United States, pointing to its relations with Russia and Iran, and doubted that India would match China's strength anytime soon.

Trump in August slapped major tariffs on India over its purchases of oil from Russia.

Lawyers for Tellis did not immediately respond to a request for comment.