The former speaker of the Ukrainian parliament Andriy Parubiy has been shot dead in the western city of Lviv, officials have said.
Unverified footage, purportedly of the shooting, appears to show a gunman dressed as a courier approaching Parubiy on the street and holding up a weapon as he walks behind him, before fleeing. A huge manhunt is now under way for the suspect.
Ukrainian President Volodymyr Zelensky described Saturday's attack as a terrible murder and offered condolences to Parubiy's family.
Parubiy, 54, rose to prominence during Ukraine's Euromaidan mass protests, which advocated closer ties with the EU and brought down pro-Russian former President Viktor Yanukovych in 2014.
A special operation, codenamed Siren, has now been launched by Ukrainian authorities aimed at tracking down and arresting the suspected shooter.
Officials have indicated that the assailant fired approximately eight shots, and police are investigating the incident as potentially well-planned. There are also inquiries into possible motives, including the possibility of Russian involvement.
Parubiy played a crucial role in the Euromaidan movement, helping to coordinate protests and self-defence teams during clashes with riot police. In his later years, he joined Ukraine's territorial defence amid the ongoing conflict with Russia.
Former President Petro Poroshenko lamented Parubiy's death, stating it was a shot fired at the heart of Ukraine and reflecting on his significant contributions to the country.