KYIV: A deadly Russian missile strike on Ukraine's southern port city of Odesa on Wednesday appeared to land near the motorcade of President Volodymyr Zelenskyy and visiting Greek Prime Minister Kyriakos Mitsotakis, who described the "intense" moment of the surprise attack.

Mitsotakis said Zelenskyy was giving him a tour of the Odesa port — a vital outlet for Ukrainian exports across the Black Sea — when "we heard sirens."

"Shortly after, as we were getting into our vehicles, we heard a powerful explosion," he said.

"We did not have time to get to a shelter. It is a very intense experience," the premier said through a translator in Odesa.

Ukraine's navy told Agence France-Presse (AFP) that the attack on port infrastructure killed five people and left an unspecified number of wounded.

Ukraine stepped up its own attacks behind Russian lines with the apparent killing of a Russian election official with a car bomb and a drone assault on a metals plant.

Russia and Ukraine have increased aerial attacks as Moscow's troops advance on the front lines and Kyiv faces a shortage of manpower and weapons.

Ukrainian navy spokesman Dmytro Pletenchuk confirmed the Odesa strike came as the Greek delegation was visiting the port with Zelenskyy.

A White House spokesman said in Washington that "it appears that [the rocket] landed near the convoy."

In Rome, Italian Prime Minister Giorgia Meloni expressed "total condemnation for the attack on Odesa during the meeting."

But Russia's Defense Ministry claimed a strike on a "hangar in a commercial port area of Odesa in which crewless cutters were being prepared for combat use by the Ukrainian armed forces."

The hit came just days after 12 people, including five children, were killed when a Russian drone hit an apartment block in the same Black Sea city, one of the deadliest attacks on civilians in weeks.

With the White House struggling to end Republican stonewalling on new US aid packages to Ukraine, a spokesman for President Joe Biden's National Security Council said the Odesa attack showed the "urgent need" for sending weapons.

"This strike is yet another reminder of how Russia is continuing to attack Ukraine recklessly every single day," the spokesman said.

Meanwhile, authorities in the Russian-occupied city of Berdyansk in southern Ukraine blamed Kyiv for a car bombing that it said killed a local election official.

"A homemade explosive device was planted under the vehicle of a member of the precinct election commission," the city's 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.

Yevgeny Balitsky, the Moscow-installed head of the Zaporizhzhia region, 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 invasion of Ukraine on Feb. 24, 2022.

Russia also said Ukraine hit a fuel tank at a plant in Russia's 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 kilometers (55 miles) from the border with Ukraine, Kursk Gov. Roman Starovoyt said.

Videos posted on Russian social media showed thick gray smoke billowing as a fire raged inside a cylindrical fuel storage tank.