By Tom Balmforth and Iryna Nazarchuk

KYIV/ODESA, Ukraine (Reuters) -Russia fired missiles and drones at targets across Ukraine in the early hours of Saturday, killing three civilians in the Black Sea city of Odesa and striking a military air field in the central Poltava region, Kyiv authorities said.

The attacks, in which a 29-year-old was also killed in the northeast Kharkiv region according to officials, were the latest in a spate of overnight strikes that Russia has intensified as Kyiv sets its sights on a major counter-offensive.

The Air Force said the attacks involved eight ground-launched missiles and 35 strike drones. Air defence units managed to down 20 drones and two cruise missiles, it said.

“As a result of the air fight, debris from one of the drones fell onto a high-rise apartment, causing a fire,” the southern military command’s spokesperson Natalia Humeniuk said of the attack on Odesa.

Firefighters battled overnight to put out the fire in the 10-storey block in a residential area of the city, footage released by the military showed.

The morning light revealed a gaping crater in the ground several metres wide next to the damaged building and a children’s playground, a Reuters photographer said.

Three people were killed including a couple who lived on the eighth floor of the building and a man who had been outside at the time of the attack, authorities said.

At least 27 other people, including three children, were hurt, the emergency services said.

The first drone strike came around midnight and was followed by three more. Air raid sirens blared repeatedly through the night.

Russia also fired drones and ballistic and cruise missiles at the Poltava region, inflicting “some damage of infrastructure and equipment” at the Myrhorod military airfield, the regional governor said.

Ten drones attacked two areas of the Kharkiv region, which borders Russia and also backs onto the front line, wounding a 39-year-old man and killing one other person, governor Oleh Synehubov.

Ukraine also shot down two drones over the Dnipropetrovsk region where no damage was reported, its governor Serhiy Lysak said.

(Reporting by Tom Balmforth; Editing by Frances Kerry)

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