A former US intelligence officer has appeared in court in Seattle charged with attempting to spy for China.
Ron Rockwell Hansen, 58, was arrested by the FBI on Saturday on his way to a Seattle airport for a flight to China.
The justice department says Mr Hansen attempted to pass on information and received at least $800,000 (£600,000) for acting as a Chinese agent.
He agreed in a brief court appearance to be returned to his home state of Utah to face charges.
What are the charges?
Mr Hansen, who lives in Syracuse, Utah, was charged with attempting to gather or deliver national defence information to aid a foreign government.
Other charges - there are 15 in total - include acting as an unregistered foreign agent for China, bulk cash smuggling, structuring monetary transactions and smuggling goods from the US.
If convicted of attempted espionage, Mr Hansen faces a maximum penalty of life in prison.
Assistant Attorney General John Demers called Mr Hansen's alleged actions "a betrayal of our nation's security" and an "affront to his former intelligence community colleagues".
John Huber, US attorney for the state of Utah, called the allegations "very troubling".
Who is Ron Hansen?
According to court documents cited by the justice department, Mr Hansen served in the US Army as a warrant officer with a background in signals intelligence and human intelligence, before being recruited by the DIA as a civilian intelligence case officer in 2006.
The justice department says Mr Hansen, who is fluent in Mandarin and Russian, held top secret clearance "for many years" and travelled regularly between the US and China in 2013-17.
He is alleged to have attempted repeatedly to regain access to classified information after he stopped working for the US government, thereby alerting authorities to his actions.
What is the DIA?
The Defense Intelligence Agency is a branch of the Department of Defense, responsible for analysing and disseminating military intelligence.
The agency's primary responsibility is providing foreign military intelligence for US combat missions. It was established in 1961 and now has about 17,000 employees.
How are US-China relations?
The arrest comes at a challenging time for relations between the two countries. On Saturday, US Defence Secretary James Mattis accused China of attempting to intimidate its neighbours by deploying missiles to disputed islands in the South China Sea.
A Chinese military official dismissed the comments as "irresponsible".
Trade talks currently taking place between the two countries in Beijing have been overshadowed by a looming start date for US tariffs on Chinese goods.
Late last month, the White House announced plans to place a 25% tariffs on $50bn (£37bn) worth of Chinese imports, a significant escalation in a trade war between the two countries.
What other spying cases have been reported?
Mr Hansen is the latest in a string of former US intelligence officers caught up in spying cases related to China:
- Jerry Chun Shing, a former CIA case officer, was charged earlier this month with conspiring to gather or deliver national defence information to China
- Former CIA officer, Kevin Mallory, is currently on trial in Virginia, charged with selling information to the Chinese