MOSCOW, Aug. 12 (Xinhua) -- Suspected saboteurs admitted that they had plotted bomb attacks in Crimea, the Interfax news agency reported Friday.

Ridvan Sulemanov, who was held by the Russian Federal Security Bureau (FSB) in Crimea, admitted that he acted upon the assignment given by the Ukrainian military intelligence service, the Interfax said, citing a video footage obtained from the FSB.

According to Sulemanov, he was tasked with travelling to Simferopol to find a place at the central coach station and the airport to plant improvised explosive devices.

Sulemanov said he was also asked to check the number of CCTV cameras in the area and the frequency of law enforcement patrols.

Zakhtei, another suspect who was said to be a driver and whose full name is not given, confessed in the interrogation video that he worked for the Ukrainian intelligence service and was recruited by suspected Ukrainian saboteurs.

"Some stranger called me ... He told me that I was supposed to come to the village of Risovo not far from Armyansk at about midnight to collect a group of people with some load. I was told not to tell anyone about this ride," the Interfax quoted Zakhtei as saying.

The Interfax also quoted an unnamed source with Russian special services saying that one person had been arrested and several more detained, and that they had started providing testimony confirming Kiev's involvement in the terror scheme.

Ukraine has yet responded to the video footage. It was not clear when the arrests were made.

Tensions between Russia and Ukraine have been escalating as Russian President Vladimir Putin on Wednesday accused Kiev of plotting terrorist attacks in Crimea after Moscow said it thwarted a series of terrorist attacks in Crimea planned by the Ukraine military intelligence service.

Putin also vowed to take additional measures to ensure the safety of infrastructure and citizens there.

Ukrainian President Petro Poroshenko, however, denied the accusations, calling them "preposterous and cynical."