Employees of private security structures of the Russian Federation are involved in the war in Ukraine, Ukraine's SBU State Security Service has said.

"Russia is engaging private security firms in the war with Ukraine. One of these 'private guards' who was captured by the Ukrainian security forces has said this," the SBU on its Telegram channel.

According to the SBU, the prisoner admitted that for $2,000 he went to work for a security company in Rostov and, as a civilian, was hired to deliver cargo, information about which was kept secret.

"Later it turned out that his task was to deliver two KAMAZ trucks carrying ammunition for the bombardment of residential areas of Kharkiv," the Ukrainian intelligence service said in the statement.