Russia fired missiles at several cities in Ukraine early Monday, with air alerts sounding in many parts of the country, according to Ukrainian authorities.
Explosions were heard in the capital Kyiv, the north-eastern city of Kharkiv and the south-eastern city of Zaporizhzhya.
Authorities called on people to seek safety in shelters.
There were reports of power cuts.
It has been 250 days since the start of Russia’s invasion of Ukraine.
Russia has declared that it is targeting the neighbouring country’s energy infrastructure in particular.
Ukraine says Moscow’s intention is to plunge people into darkness, cold and fear, thus driving them to flee to the European Union.
