A communications officer at the U.S. Consulate in Istanbul was arrested on charges of political and military espionage and attempting to overthrow the Turkish government, allegations that the U.S. government said were “baseless” and “wholly without merit.”

Turkish media reported that Metin Topuz, who worked as a communications officer at the U.S. Consulate in Istanbul before 2013 twin corruption investigations that targeted then-Prime Minister Recep Tayyip Erdogan and his inner circle, stayed in touch with Turkish law enforcement officials who supervised the corruption investigations.

Mr. Topuz was detained four days ago as part of a confidential probe and arrested pending trial on Wednesday. He was accused of talking to Zekeriya Oz, the prosecutor who supervised the corruption investigations, and police chiefs who carried out the operations against sons of Turkish ministers and dozens of other suspects.

One of the suspects included one of the sons of Mr. Erdogan, who described the operation back then as a coup attempt with “global links.” The operations also put Iranian gold trader Reza Zarrab behind bars, but he was soon released from prison under political pressure. Mr. Zarrab is currently in a federal U.S. prison in Manhattan and facing charges of violating U.S. sanctions on Iran.

Earlier last month, the U.S. issued an arrest warrant for ex-Turkish minister Zafer Caglayan, whose son was arrested during 2013 corruption operations in Istanbul and soon released.

Following the indictment of Mr. Caglayan, Turkey started a hunt of those who allegedly informed the U.S. about the corruption cases.

On Thursday, U.S. Embassy in Turkey said the U.S. government is “deeply disturbed” by the arrest of Mr. Topuz. It added that leaks from Turkish government sources seemingly aimed at trying the employee in the media rather than a court of law.

“We believe these allegations to be wholly without merit,” the embassy said, adding that the U.S. will continue to engage with the Turkish government to ensure that employees of the U.S. government, as well as American citizens in Turkey, are accorded due legal process in accordance with the Turkish constitution and international legal norms.

“Baseless, anonymous allegations against our employees undermine and devalue this longstanding partnership.”