A suspected agent for the Russian government has been found working in the US Embassy in Moscow. The unidentified Russian woman worked for the Secret Service as a liaison between the agency and Russia’s law enforcement and intelligence agencies.

The suspect reportedly worked in the embassy for more than a decade. A routine investigation in 2016 found that the woman was having regular unauthorized meetings with members of Kremlin’s Federal Security Service (FSB). The agency quietly fired her in 2017 without an investigation.

The Secret Service has claimed that no foreign nationals had any access to information pertaining to national security. However, an unidentified source familiar with the situation said the woman had access to the agency’s email and intranet system, which included presidential and vice presidential schedules.

In a statement on the matter, the agency wrote: “The US Secret Service recognizes that all Foreign Service Nationals (FSN) who provide services in furtherance of our mission, administrative or otherwise, can be subjected to foreign intelligence influence. At no time, in any U.S. Secret Service office, have FSNs been provided or placed in a position to obtain national security information.”

According to a source with knowledge of the matter, the woman was actually employed by the State Department, but worked for the Secret Service as part of her job at the embassy. Technically, all foreign nationals working for the federal government are employed by the State Department, then assigned to work with different agencies. The State Department has declined to comment on the matter.

The woman’s firing reportedly occurred shortly before more than 700 U.S. diplomats and staff were expelled from Russia by Russian President Vladimir Putin in August 2017. Those expulsions were widely believed to be in retaliation to economic sanctions imposed on the country and some of its highest profile citizens by Congress.