A grenade launcher fired at the building of a Ukrainian television channel on Saturday after it announced plans to air a controversial documentary featuring Russian President Vladimir Putin.
The attack at around 3.40am (1.40 CET), described as terrorism by officials, caused no injuries but damaged a sign on the facade of the offices of "112 Ukraine" channel, police said.
A grenade-launcher was abandoned at the scene.
Police officers tightened security controls in the capital Kiev in a bid to detain the person responsible.
The incident is being investigated by the SBU, the state security service.
The channel's CEO Yegor Benkendorf in a statement appealed to Ukrainian President Volodymyr Zelensky to "immediately condemn criminal acts" against the channel.
"You must state clearly and decisively that no one should use force against media in Ukraine," Benkendorf said.
The channel, owned by pro-Russian MP Taras Kozak, received a warning this week from Ukrainian prosecutors over plans to show a documentary by US filmmaker Oliver Stone called "Revealing Ukraine", which includes an interview with Putin.
In the documentary, Putin and pro-Russian politician Viktor Medvedchuk comment on events in Ukraine.
The owner of "112 Ukraine" channel, Kozak, is considered to be a close ally of Medvedchuk, a controversial figure because of his ties to Putin.
Kiev has been fighting a war against Moscow-backed separatists in eastern Ukraine since 2014.
Ukraine's Prosecutor-General Yuriy Lutsenko on Thursday described the documentary as a "Russian propaganda film" and said everyone involved in its broadcast would be called in for questioning.
On Friday "112 Ukraine" had warned its team had received a "direct threat of physical attack" from radical organisations due to the documentary, which was due to be shown next week.
The channel has now cancelled the broadcast, saying it was to avoid possible sanctions and criminal prosecution.