Three citizens of Russia and three Ukrainians, who were the members of a sabotage and reconnaissance group, were detained during a police operation in Ukraine, Ukrainian Security Service (SBU) spokesperson Olena Hitlianska has said.

"Two citizens of the Russian Federation and three citizens of Ukraine have been detained," Hitlianska wrote on her Facebook account.

Another man, a member of this sabotage group, was killed in a shootout, she said. Two officers of the Ukrainian special operations unit Alfa were wounded during the operation.

Hitlianska wrote in her comments later that one more Russian citizen had been detained.

"An examination of the scene continues. Eight loaded improvised explosive devices, four kilograms of TNT, automatic weapons, more than 40 grenades, some 2,000 cartridges, as well as parts of explosive devices and ordnance have been confiscated from only one of the addresses in the capital," she said.

On Thursday morning Advisor of the SBU Chief Yuriy Tandyt confirmed a death of one of the wounded officers of Alfa.