Ukrainian investigators have opened a criminal case on the basis of a report made by the relatives of Yevhen Panov, leader of the Self-Defense group in the town of Enerhodar, Zaporizhia region, acting head of the Ukrainian National Police Vadym Troyan said on Thursday.

The National Police's Communications Department said investigators had qualified the Panov missing person case under Article 146 (illegal imprisonment or abduction of a person) of the Ukrainian Criminal Code.

Troyan said Panov's relatives reported him missing to the police on Wednesday, August 10, after which the information was entered into the national register of pre-trial investigations. "We are taking all necessary measures to promptly, fully and impartially investigate all circumstances of this crime," Troyan said.

On August 10, the Russian Federal Security Service said terrorist acts allegedly prepared by Ukrainian intelligence had been averted in Crimea. It was reported that the Russian special services, with support from other defense and security units, had prevented groups of saboteurs and terrorists from breaking into Crimea from the territory of Ukraine.

The Russian Federal Security Service also said one of the organizers, "Panov Yevhen Oleksandrovych, 39, a resident of Zaporizhia region, an official with the Main Intelligence Department of the Defense Ministry of Ukraine," had been detained. He is making confessionary statements.

The Ukrainian Defense Ministry, the Main Intelligence Department and the National Security and Defense Council have denied the reports on Ukrainian saboteurs. The Defense Ministry also said the accusations made by Russia of attacks on the peninsula from mainland Ukraine are similarly groundless.

Panov's brother Ihor Kotelianets said he thought Yevhen had been abducted in Zaporizhia region and taken to Crimea.