Two former French spies have been charged with treason for spying for a foreign power, the defence ministry has confirmed, with judicial sources saying the power in question is China.

The two retired spies, along with the spouse of one of the accused pair, were arrested in December, said armed forces minister Florence Parly, warning that the compromised information “could undermine the security of the state”.

The agents are thought to have handed over secrets while still in service for France’s external DGSE intelligence agency, similar to Britain’s MI6 and America’s CIA, Ms Parly told CNews television.

She declined to comment on unconfirmed reports that China was the foreign power in question, however sources close to the investigation told AFP that this was the case.

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

One of the former agents, whose identities have not be disclosed, also faces charges of directly inciting treason, the source said.