Activists hold a banner reading "Why do we need SBU?" as they burn flares and smoke bombs during a protest action in front of Ukraine's Security Service (SBU) head office in Kiev on July 13, 2019. - They protest against plans to show a documentary film by US filmmaker Oliver Stone called "Revealing Ukraine" on the "112 Ukraine" television channel, with the controversial documentary featuring Russian President Vladimir Putin. "112 Ukraine" channel building was attacked last night an unknown person with a grenade-launcher in Kiev. (Photo by SERGEI SUPINSKY / AFP)

Activists burn flares and smoke bombs as they take part in a protest action in front of Ukraine's Security Service (SBU) head office in Kiev on July 13, 2019. - They protest against plans to show a documentary film by US filmmaker Oliver Stone called "Revealing Ukraine" on the "112 Ukraine" television channel, with the controversial documentary featuring Russian President Vladimir Putin. "112 Ukraine" channel building was attacked last night an unknown person with a grenade-launcher in Kiev. (Photo by SERGEI SUPINSKY / AFP)

Activists hold a banner reading "Why do we need SBU?" as they burn flares and smoke bombs during a protest action in front of Ukraine's Security Service (SBU) head office in Kiev on July 13, 2019. - They protest against plans to show a documentary film by US filmmaker Oliver Stone called "Revealing Ukraine" on the "112 Ukraine" television channel, with the controversial documentary featuring Russian President Vladimir Putin. "112 Ukraine" channel building was attacked last night an unknown person with a grenade-launcher in Kiev. (Photo by SERGEI SUPINSKY / AFP)

Activists hold a banner as they burn flares and smoke bombs during a protest action in front of Ukraine's Security Service (SBU) head office in Kiev on July 13, 2019. - They protest against plans to show a documentary film by US filmmaker Oliver Stone called "Revealing Ukraine" on the "112 Ukraine" television channel, with the controversial documentary featuring Russian President Vladimir Putin. "112 Ukraine" channel building was attacked last night an unknown person with a grenade-launcher in Kiev. (Photo by SERGEI SUPINSKY / AFP)

Activists hold a banner reading "Why do we need SBU?" as they burn flares and smoke bombs during a protest action in front of Ukraine's Security Service (SBU) head office in Kiev on July 13, 2019. - They protest against plans to show a documentary film by US filmmaker Oliver Stone called "Revealing Ukraine" on the "112 Ukraine" television channel, with the controversial documentary featuring Russian President Vladimir Putin. "112 Ukraine" channel building was attacked last night an unknown person with a grenade-launcher in Kiev. (Photo by SERGEI SUPINSKY / AFP)

An activist holds palcard reading "112 channel smells enemy's propaganda" during protest action in front of Ukraine's Security Service(SBU) head office in Kiev on July 13, 2019, as policemen stand guard at the entrance. - They protest against plans to show a documentary film by US filmmaker Oliver Stone called "Revealing Ukraine" on the "112 Ukraine" television channel, with the controversial documentary featuring Russian President Vladimir Putin. "112 Ukraine" channel building was attacked last night an unknown person with a grenade-launcher in Kiev. (Photo by SERGEI SUPINSKY / AFP)