“The number of people killed in the enemy attack on the outskirts of Kharkiv has reached four,” Oleg Synegubov posted on Telegram.

He also said six people were wounded in the overnight attack.

Kharkiv Mayor Igor Terekhov said a Russian long-range drone struck a medical facility for children, causing a fire.

Moscow has pummelled Ukraine with daily drone and missile barrages in recent months, targeting energy infrastructure and cutting power in the frigid height of winter.

Russia’s use last week of a nuclear-capable Oreshnik ballistic missile on Ukraine sparked condemnation from Kyiv’s allies, including Washington, which called it a “dangerous and inexplicable escalation of this war”.

Moscow on Monday said the missile hit an aviation repair factory in the Lviv region and that it was fired in response to Ukraine’s attempt to strike one of Russian President Vladimir Putin’s residences — a claim Kyiv denies.