The Ukrainian Security Service (SBU) has described the information circulated in the Russian media about the alleged arrest of a group of Ukrainian citizens on suspicion of preparing subversive activities in Russia as "nonsense".

"We do not comment on nonsense," the SBU press service told Interfax-Ukraine on Thursday.

Earlier, the press service of the Right Sector party also called the claims of the Russian media that their party activists were among the detained Ukrainians as rubbish.

NTV television earlier reported that twenty-five citizens of Ukraine, including three Right Sector activists, were detained on suspicion of preparing subversive activities on the territory of Russia. NTV aired a video of the detained Ukrainian citizens.

According to information possessed by the special services, the terrorist attacks were expected to take place in seven Russian regions (Rostov, Volgograd, Oryol, and Belgorod regions, and the Republics of Kalmykia and Tatarstan) on March 14 - 16, the report says.

The channel said that the 25 detainees, among which are three Right Sector activists, have confirmed that they have received instructions from Ukrainian security service officials.

Their tasks included photographing the location and transfer of military equipment and the Russian Armed Forces in the areas close to the border and establishing contacts with Russian radical structures. The detainees are currently being interrogated.

The Ukrainian Foreign Ministry told Interfax-Ukraine they were checking these reports.