A three-year-old and a woman together with her infant child were reported to be among the dead.
"Rescuers in Odesa have just uncovered the bodies of a mother with a three-month-old baby," Interior Minister Ihor Klymenko said in a post on his Telegram channel beside a photograph of a rescue worker next to a bloodied blanket, a baby's arm visible on one side and an adult arm extending out the other.
Regional governor Oleh Kiper said a further eight people were injured. He added that the drone was shot down by Ukrainian air defences, and that the falling debris hit the apartment building.
"Russia continues to fight civilians ... One of the enemy drones hit a residential building in Odesa. Eighteen apartments were destroyed," Ukrainian President Volodymyr Zelenskiy said in a Telegram post. Zelenskiy said the drone was a Iranian-supplied Shahed.
Ukraine's armed forces reported that the Odesa region was attacked by eight drones, of which seven were shot down by air defences.
Across the country more widely, air defences shot down 14 of 17 drones launched against Ukraine, officials said.
Kharkiv regional governor Oleh Syniehubov reported on Saturday morning that more than 20 settlements in the eastern Ukrainian province had sustained Russian artillery and mortar attacks. He said that there were no casualties.
In the partly occupied Kherson region, Russian artillery shelling killed a 53-year-old man on Saturday morning, the Kherson regional prosecutor's office said.
Meanwhile, in Russia, a drone crashed into an apartment building in St Petersburg, according to state news agency RIA Novosti.
Damage is assessed at an apartment building in St Petersburg after a reported drone attack. (AP PHOTO)
Six people received medical help after the explosion rocked the building, the agency said.
The Mash news site said the apartment building was hit by a Ukrainian drone.
The site published videos appearing to show the moment the apartment building was struck, showing a strong flash of light engulfing one side of the building and fragments of debris flying into the air.
St Petersburg Governor Alexander Beglov said two buildings were damaged and residents had been evacuated after what he called an "incident" with no casualties.
with Reuters
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