A former US diplomatic officer has been arrested and charged with giving top-secret documents to a Chinese agent.

According to the affidavit, Kevin Mallory, a 60-year-old from Virginia, is said to have travelled to Shanghai in March and April 2017.

He was interviewed by customs agents an airport in Chicago after he failed to declare $16,500 (£13,000) in cash found in two carry-on bags.

A senior justice official said the allegations were “serious”.

“The conduct alleged in this complaint is serious, and these charges should send a message to anyone who would consider violating the public’s trust and compromising our national security by disclosing classified information,” said Dana J Boente, Acting Assistant Attorney General for National Security.