Eight people have been killed across Ukraine in overnight and early morning Russian attacks, local officials say.

In the Black Sea port of Odesa, three people were killed and another three injured in a “massive” drone and missile strike, regional head Oleh Kiper said. It was the fifth day in which Russia has hit the region.

In the north-eastern city of Sumy, three people were killed and 17 injured in shelling by guided aerial bombs, said acting Mayor Artem Kobzar. Another two casualties were reported in the central Dnipropetrovsk region and Zaporizhzhia, in the south.

Meanwhile, Ukraine’s military said its drones hit 20 Russian vessels, including 17 oil tankers, in the Black Sea overnight.

The Russian ministry of defence confirmed it had attacked Odesa, saying it had deliberately targeted port infrastructure, “used for the unloading of petroleum, oil, and lubricants”.

Writing on Telegram, Kiper accused Russia of deliberately targeting the civilian population and said residents were killed and injured when a Russian missile struck a multi-storey residential building.

He added that a non-residential building and a gas pipeline were also hit.

In its report issued on Tuesday, the United Nations Human Rights Monitoring Mission in Ukraine said at least 293 civilians were killed and 1,990 injured in Ukraine in June.

It said that long-range weapons – such as missiles and drones – “remained the leading cause of civilian casualties”, accounting for 45% of deaths.

“Most casualties from these weapons occurred far from the front line in urban centres such as Kyiv and Dnipro,” the UN monitors said.

In its statement, Russia’s military claimed to have targeted sites involved in the manufacture of military hardware, and the transport of cargo.

Russia’s attacks in recent days have targeted Ukraine’s deep-water Black Sea ports in the wider Odesa area, which handle much of the country’s grain and other cargo and are vital to its wartime economy.

It follows intensive attacks on Russian ships in the Sea of Azov, which sits between the Moscow-annexed Crimea and Russia.

The Ukrainian attacks have forced Russia, the world’s top grain exporter, to restrict shipping in the Sea of Azov – a route that handles about a quarter of its grain exports, according to news agency Reuters.