PARIS (Reuters) - Two French former spies could face trial for treason over allegations that they passed state secrets to a foreign power, France’s defense ministry said.

Confirming the December arrests of two retired spies, along with the spouse of one of the accused pair, Armed Forces Minister Florence Parly said on Friday the compromised information “could undermine the security of the state”.

Quotidien, a TV show which first revealed the spying case, said China was involved.

A close adviser to President Emmanuel Macron on Friday stayed mum over which foreign country had obtained information from the agents, but suggested such a scenario would not derail relations between Paris and Beijing.

“We’re two big powers who know each other well,” the Macron adviser told reporters.

Chinese foreign ministry spokesman Lu Kang declined to comment when asked about the allegations at a daily briefing in Beijing.

The agents are believed to have handed over secrets while still in service for France’s DGSE intelligence agency, Parly said on CNews television. She declined to comment on unconfirmed reports that China was the foreign power in question.

Both were placed under formal investigation on Dec. 22 to face charges of spying for a foreign power, compromising classified secrets and delivering information detrimental to fundamental national interests, a judicial source told Reuters.

One of the former agents, who have not been identified, also faces charges of directly inciting treason, the source said.

French authorities have not said how recently the alleged double agents are thought to have been operating.

The DGSE itself contacted French prosecutors after uncovering the “extremely serious” behavior of its agents, the defense ministry said in a statement late on Thursday.

“The fact that we sounded the alert is proof of our vigilance,” Parly said.