The Ukrainian army has taken all necessary measures to ensure the security of the trilateral Contact Group, made up of representatives of Ukraine, Russia and the Organization for Security and Cooperation in Europe (OSCE), who arrived in Donbas recently, spokesman for the anti-terrorist operation in the east Vladyslav Selezniov told Interfax-Ukraine.

"The first representatives arrived yesterday, and they are supposed to begin working today," he said, declining to provide further details.