Two children were among 11 people killed when a Russian missile hit a residential building in Ukraine's northeastern city of Sumy, Ukrainian officials said, while another missile strike left the region's administrative centre without power.

Russian forces attacked Mykolayiv with Shahed-131 and Shahed-136 drones at around 1:50 a.m. local time, killing five and injuring one, regional governor Vitaliy Kim said in a post on Telegram

At least six people were killed and 23 others injured in overnight strikes in the cities of Mykolayiv and Zaporizhzhia in southern Ukraine on Monday, local authorities said.

Officials said a further 18 people, including five children, were injured in the Russian air strikes in the Mykolaiv and Zaporizhzhia regions. Meanwhile, US President-elect Trump has spoken with Putin about the war.

Officials said a further 18 people, including five children, were injured in the Russian air strikes in the Mykolaiv and Zaporizhzhia regions. Meanwhile, Putin and US President-elect Trump reportedly spoke about the war.

Authorities in Ukraine have said Russian air strikes killed at least five people in the south of the country, a day after both sides launched record overnight drone attacks on each other.