The Ukrainian Security Service says that it has arrested seven Russian nationals who are believed to have been plotting attacks in Ukraine, but one of the suspects says he is safe in Russia.

Ukraine's intelligence agency, which is also known as the SBU, said Wednesday that two of the seven men claim to work for Russian intelligence but offered no documentation to back up this claim.

The arrests come days before Ukrainians vote in the presidential election runoff.

One of the men named by the SBU, Timur Dzortov, who is an official in the North Caucasus region of Ingushetia, told Radio Free Europe that he has not been arrested and that he is currently in his office in the city of Magas.

The SBU was not immediately available for comment.