Ukraine stepped up attacks behind Russian lines on Wednesday with the apparent killing of a Russian election official in a car bomb and a drone assault on a metals plant.
Strikes also rocked the Ukrainian port city of Odesa during a visit by Greek Prime Minister Kyriakos Mitsotakis, who was holding talks in the city with Ukrainian President Volodymyr Zelensky.
Both Russia and Ukraine have increased their aerial attacks as Moscow's troops advance on the frontlines and Kyiv faces a shortage of manpower and weapons.
"We heard the sound of sirens and explosions that took place near us. We did not have time to get to a shelter. It is a very intense experience," Mitsotakis said through a translator in Odesa.
Zelensky said the strike had left "dead and wounded", but he did not have figures.
"You can see who we are facing. They don't care where they strike," he he told the joint press conference.
The apparent hit comes just days after 12 people, including five children, were killed when a Russian drone hit an apartment block in the Black Sea city, one of the deadliest attacks on civilians for weeks.
Car bomb
Authorities in the Russian-occupied city of Berdyansk in southern Ukraine said a local election official had been killed in a car bombing it blamed on Kyiv.
"A homemade explosive device was planted under the vehicle of a member of the precinct election commission," the Investigative Committee said in a statement.
"The victim died from her injuries," it added, publishing a video of a blown-out small beige car parked on a dirt track.
The attack came with early voting already underway across occupied Ukraine for this month's Russian presidential election.
The Moscow-installed head of the Zaporizhzhia region Yevgeny Balitsky blamed Ukrainian authorities for the attack and said they were trying to "intimidate" residents ahead of the ballot.
A number of Russian-installed officials have been targeted since Moscow launched its full-scale military operation in Ukraine two years ago.
Russia also said Ukraine hit a fuel tank at a metals plant in the Kursk region in an early morning drone strike.
"A drone attacked a fuel and lubricants warehouse," at the Mikhailovsky Mining and Processing Plant in the city of Zheleznogorsk, some 90 kilometres (55 miles) from the border with Ukraine, Kursk governor Roman Starovoyt said.
Videos posted on Russian social media showed thick grey smoke billowing as a fire raged inside a cylindrical fuel storage tank.
Fortifications
Ukrainian forces have launched a wave of drone attacks at Russian energy facilities in recent months, trying to target the country's vital energy and gas sector that it says fuels the invasion.
Meanwhile, Russian-installed officials said a Ukrainian artillery strike on Kreminna, a town in Ukraine's Lugansk region, killed two people.
Five more were killed when a bus drove over a mine in Kirovsk, also in Lugansk, the Moscow-appointed head of the region said.
Lugansk is one of the four Ukrainian regions -- along with Donetsk, Kherson and Zaporizhzhia -- that Russia claimed to annex in 2022.
The region has been at war since 2014 when Russian-backed separatists tried to secede following a pro-EU revolution in Kyiv.
On the frontlines, the Ukrainian army said Wednesday it had built an "extensive system" of fortifications near the town of Adviivka -- captured last month by Russia -- in a bid to stop further Russian advances.
Hold-ups to Western aid, mainly a crucial $60-billion package from the United States, have left Ukraine's troops in a vulnerable position, forced to ration ammunition and unable to mount large-scale offensives.
'Active combat zone'
Russian President Vladimir Putin also held talks with the head of the International Atomic Energy Agency, Rafael Grossi, in Sochi to discuss the situation at the Zaporizhzhia nuclear power plant.
The facility, Europe's largest nuclear energy site, was seized by Russian troops in the first days of the war.
Speaking to AFP ahead of the meeting, Grossi rejected Russian suggestions that the plant could be put back online.
"That is not imminent," he told AFP in response to suggestions by the Russian operator that it could be switched back on.
"First of all, this is an active combat zone, and this cannot be forgotten. Secondly, this plant has been in shutdown for a prolonged period of time," he added.