Russia launched a “massive” missile and drone attack against Ukraine overnight, targeting energy infrastructure across the country, Kyiv’s energy minister said.

A nationwide air raid alert was issued after Russia launched seven Tu-95 strategic bombers, the Ukrainian air force said.

Explosions were heard in several cities, including in Kyiv, Kharkiv, Mykolaiv, Odesa, Lutsk, and Rivne. Local officials also said there were strikes in Sumy, Lviv, and Vinnytsia.

Emergency power outages were introduced in Kyiv, Odesa, Dnipro, and Donetsk as a result of the strikes, energy provider DTEK said.

Volodymyr Zelensky’s chief of staff said the attack showed Russia was “continuing their tactics of terror”.

It follows a warning by the United Nations that Russian strikes on Ukraine’s energy infrastructure may make this winter the “harshest since the start of the war”.