Fighting intensifies in Ukraine's southern Zaporizhzhia region on Friday, a Russian official says.

Ukraine says Russian forces have achieved some success in the frontline city of Bakhmut.

Various missiles, including the hypersonic Kinzhal, pounded the capital and other Ukrainian cities.

Russia has launched a fresh wave of missile attacks on Ukraine, targeting the country's critical infrastructure and causing power outages and disruptions in train services, according to Ukrainian officials and media. 

The Russian army said it had taken "more advantageous lines and positions" after "offensive operations" in Zaporizhzhia.

Russian President Vladimir Putin says the situation in four former regions of Ukraine that recently voted to join the Russian union is "extremely complicated", urging the country’s security agencies to remain vigilant.

Russia's Defense Ministry said, "Not a single strike was made on targets within the city of Kiev."