Ukraine is accusing Russia of killing 13 and injuring 10 after firing rockets at towns near the Zaporizhzhia region.
The attacks were reported to have been launched near the Zaporizhzhia plant, which Russia seized in March.
Moscow has claimed Ukraine has used Ukraine in the past to shell Russian soldiers at the Zaporizhzhia plant, which was the brunt of the attacks in the town of Marhanets.
Ukraine President Volodymyr Zelenskyy said Ukrainian forces would respond to the shelling of Marhanets.
Ukraine said Russia also bombarded several other areas of the Zaporizhzhia region, including the coal-mining town of Vuhledar, the Dnipropetrovsk region and Donetsk in the country's east.
In a late-night video address, Mr Zelenskyy said that Ukrainians and the country's allies must think about how to shorten the war Ukraine and Russia have accused each other of imperiling the Zaporizhzhia plant, Europe's largest nuclear complex, with attacks near the site of the Russian shelling of the Dnipropetrovsk region.
After the UN atomic energy watchdog sounded the alarm over a potential nuclear disaster, G 7 members told Russia to hand back the plant to Ukraine.
There was no indication that their demand will affect Moscow, which received strong support from China for its rationale for the Ukraine invasion.
Beijing's ambassador to Moscow, Zhang Hanhui, accused Washington of backing Russia into a corner with repeated expansions of the western NATO military alliance and support for Ukraine's alignment with the European Union.
Washington's ultimate goal is to end and crush Russia with a protracted war and a cudgel of sanctions, Mr Zhang was quoted as saying.
Beijing is involved in a standoff with the United States over Taiwan. China has conducted extensive military drills since the visit of US House Speaker Nancy Pelosi to the island.
Russia has not commented on Ukrainian allegations of an attack on Marhanets and Reuters could not independently verify Kyiv's version.
Andriy Yermak, chief of staff of Zelenskyy, said Russia was launching attacks with impunity from Zaporizhzhia, knowing it was risky for Ukraine to fight back.
Ukraine said around 500 Russian troops with heavy vehicles and weapons are at the plant, where Ukrainian technicians are still working.
Ukraine's state nuclear power firm warned that containers with radioactive material could be shelled and said it is vital for Kyiv to retake the plant by winter. Russia is accused of wanting to connect the facility to its power grid.
The United Kingdom says Russia is almost certainly establishing a new ground force to back its war.
The UK Defence Ministry said in an intelligence bulletin that the new 3rd Army Corps was based in the city of Mulino, east of Moscow.
It said that Russia would struggle to build up the numbers needed and that the new force would not sway the war.
Ukraine was given economic relief after overseas creditors backed Kyiv's request for a two-year freeze on payments on almost 20 billion $28 billion in international bonds.
Ukrainian Prime Minister Denys Shmyhal said the deal would save his country almost US 6 billion.