Ukrainian troops bolstered by stepped-up supplies of Western military aid on Monday started a long-awaited counter-offensive to retake territory in the south seized by Russian forces since their invasion six months ago.
However, the southern port city of Mykoliav came under heavy Russian shelling, with the mayor saying homes had been hit and at least two people killed.
Meanwhile a team from the United Nations nuclear watchdog headed to Ukraine to inspect the Zaporizhzhia nuclear plant - captured by Russian forces in March but still run by Ukrainian staff - that has become a highly dangerous frontline in the war.
Moscow and Kyiv have traded accusations of shelling in the vicinity of the nuclear plant, Europe's largest, amid fears of a radiation leak in a country still haunted by the 1986 Chornobyl disaster.
The spokeswoman for Ukraine's southern command, Natalia Humeniuk, said its troops had started offensive actions in several directions in the south, including in the Kherson region.
Ammunition dumps hit
Russia rapidly captured swathes of Ukraine's south near the Black Sea coast, including the city of Kherson, in the early phase of the war.
The Kherson region lies north of the Russian-annexed Crimean peninsula and has coasts on the Black Sea and the Sea of Azov.
Ukraine has been using sophisticated Western-supplied weapons to hit Russian ammunition dumps and wreak havoc with supply lines. Humeniuk told a briefing that Ukraine had struck more than 10 dumps in the past week and they had "unquestionably weakened the enemy".
She declined to give details of the counter-offensive, saying Russian forces in southern Ukraine remained "quite powerful".
The governor of Crimea, Sergei Aksyonov, dismissed her announcement as "Ukrainian propaganda".
Russia's RIA news agency, quoting local official Vladimir Leontiev, said people were being evacuated from workplaces in Nova Kahokva, a town 58 km (36 miles) to the east of Kherson, after Ukrainian forces carried out more than 10 missile strikes.
To the west of Kherson, the city of Mykolaiv came under heavy Russian fire on Monday, local officials said.
Mayor Oleksandr Senkevych said two people had been killed and five wounded. Residential homes and educational institutions had been hit, he wrote on Telegram.
Mykolaiv, a shipbuilding center and river port just off the Black Sea, has suffered heavy Russian bombardments throughout the war.
Nuclear safety
The head of the International Atomic Agency (IAEA) said he would lead a team of inspectors to the Zaporizhzhia plant on the Dnipro river in southern central Ukraine.
"We must protect the safety and security of Ukraine's and Europe's biggest nuclear facility," Rafael Grossi said on Twitter.
The IAEA said separately the mission would assess physical damage, evaluate working conditions, and check safety and security systems. It would also "perform urgent safeguards activities", a reference to keeping track of nuclear material.
On Monday Russian-installed officials said a Ukrainian missile strike had punched a hole in the roof of a fuel depot at the Zaporizhzhia plant.
Russia's defense ministry said its forces had shot down a Ukrainian drone that was trying to attack the nuclear power station, Russian news agencies reported. It said there was no serious damage and radiation levels were normal.
Reuters could not independently verify either report.
The Kremlin said the IAEA mission was "necessary" and urged the international community to pressure Ukraine to reduce military tensions at the plant.
The United Nations, United States and Ukraine have called for a withdrawal of military equipment and personnel from the nuclear complex to ensure it is not a target. But the Kremlin again ruled out vacating the site.
Russian foreign ministry spokeswoman Maria Zakharova said the IAEA mission must carry out its work in a politically neutral manner.
Russian forces fired at Enerhodar, the Dnipro riverside town where the plant is located, Ukrainian President Volodymyr Zelenskiy's chief of staff said on Sunday on his Telegram channel alongside a video of firefighters dousing burning cars.
Liliia Vaulina, 22, one of a growing number of refugees from Enerhodar arriving in the Ukraine-held city of Zaporizhzhia, some 50 km (30 miles) upriver from the plant, said she hoped the IAEA mission would lead to a demilitarization of its area.
"I think that they will stop the bombing," she told Reuters.
‘Every shell matters’
In the Donetsk region of eastern Ukraine, Russian forces shelled military and civilian infrastructure near Bakhmut, Shumy, Yakovlivka, Zaytsevo, and Kodema, Ukraine's military said early on Monday.
Russia calls its actions in Ukraine a "special military operation" to demilitarize its southern neighbor. Ukraine, which won independence when the Russian-dominated Soviet Union broke up in 1991, and its Western allies have dismissed this as a baseless pretext for a war of conquest.
Thousands of people have been killed, millions displaced and cities blasted to ruins. The war has also threatened the global economy with an energy and food supply crisis.
Sweden, which along with Finland plans to join NATO in response to Russia's invasion, announced nearly $50 million worth of additional military aid to Ukraine on Monday during a visit to Stockholm by Ukrainian Foreign Minister Dmytro Kuleba.
Kuleba urged Sweden to provide weapons such as howitzers and shells. "Every euro, every bullet, every shell matters," he said.
Germany will also send more arms to Ukraine in coming weeks and help upgrade Kyiv's artillery and air defense capacities, Chancellor Olaf Scholz told a conference in Prague.
