A Russian woman worked as a spy inside the United States embassy in Moscow for over a decade before she was discovered, it has been reported.

The woman, who had her security clearance revoked in the summer of 2017, had access to the secret service’s intranet and email systems, according to The Guardian.

Those files gave her a window into potentially confidential material, including the schedules of the president and vice-president.

Suspicion was aroused in 2016, during a routine check from the state department, when it emerged she was having regular and unauthorised meetings with members of the FSB, Russia’s principle security agency.

A source told the paper that “her frequent contacts with the FSB gave her away ... numerous unsanctioned meetings and communications”.