Seven people, three of them children, have been killed in Ukraine’s western city of Lviv, according to the mayor, during a fresh wave of Russian attacks.

The strike came as Ukraine was still reeling from the deaths of at least 50 people at a military institute in the central city of Poltava on Tuesday.

Lviv Mayor Andriy Sadovy said Russia had attacked with drones and hypersonic missiles early on Wednesday.

Among those killed were a baby, a 14-year-old girl and a woman working as a midwife in the city, officials said.

Explosions were also heard over the capital Kyiv as air defences targeted Russian missiles. Meanwhile, five people were reportedly injured after flats were hit in the city of Kryvyy Rih.

The Ukrainian military said the whole country has been placed under an air alert.

Mr Sadovy said a number of residential buildings were on fire, with two schools to remain shut on Wednesday as a result of the attacks.

Rescue workers are continuing to search through the rubble of a military institute in Poltava for survivors of Tuesday’s attack.