(CNN) Senate Democrats have called on the European Union to introduce fresh sanctions against Yevgeny Prighozin, the man believed to behind many Russian troll operations, as a result of the CNN investigation that published Thursday and exposed a Russian troll farm in Ghana.

Five leading senators signed the letter calling for coordinated sanctions against Prigozhin.

"As the presidential election in the United States draws closer, our concerns about foreign interference here have intensified," the senators write. "These threats, however, are not limited to the United States — given the broad reach and expanding nature of Prigozhin and the Wagner Group's malign activities abroad, we urge the European Union to take steps to constrain their ability to operate and to deter the Kremlin from engaging in these activities."

"The U.S. and European Union should be unified in facing this common threat and take concrete measures to isolate this malign actor and his affiliated firms. This includes sanctions, but also a joint diplomatic approach to urge that countries avoid engaging with Mr. Prigozhin, Wagner and any other organization associated with him."

On Thursday, CNN revealed that a Russian troll farm based out of Ghana and Nigeria was operating under the front of an NGO called EBLA, Eliminating Barriers for the Liberation of Africa.

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