At least 21 people were killed and 48 wounded in "heavy" Russian shelling on Wednesday on Ukraine's Kherson region (south), while Ukrainian President Volodymyr Zelensky stressed during a surprise visit to Finland that this year will be "decisive".

The Ukrainian presidency announced a large-scale Russian attack on the Kherson region, noting that the death toll rose to 21 people and 48 others were wounded with "varying injuries."

Earlier in the day, Ukrainian authorities announced a 58-hour curfew in Kherson near the southern front line from Friday evening, as Kiev says it has completed preparations for a large-scale offensive.

"From 20:00 (17:00 GMT) on May 06, a curfew will be imposed in Kherson and will last until 00:03 am (00:<> GMT) on May <>," local military department chief Oleksandr Prokudin said on Telegram.

"During these 58 hours, movement on the streets of the city will be prohibited. It will also be forbidden to leave and enter Kherson."

Procoden justified the "temporary restrictions" by citing the "necessity" that "security forces can do their job," without giving further details.

The authorities' announcement comes as Kiev said its preparations for a large-scale offensive to retake Russian-occupied territory in the east and south of the country were "coming to an end".

Russia still controls about 20 percent of Ukraine, including Crimea, which Moscow annexed in 2014. Kherson, which was captured by Russian forces for months in 2022, was retaken by Ukraine last November following a successful Kiev counteroffensive in the region.

Since then, the city has been regularly bombed and the Russian army is deployed on the other side of the river, which forms a de facto front line.


Crimean region

In the Crimea region, Russian authorities there announced the downing of two drones over Crimea.

On Tuesday night, fire consumed a fuel depot in the Russian village of Volna in the Krasnodarsky region near Crimea.

Vinamin Kondratiev, governor of the Krasnodarsky Krai region, where the village is located, said: "A tank containing oil products caught fire in the village of Volna in the Temryoksky region. The fire was very serious," he said, without explaining what caused it.

According to a source in the rescue services quoted by the official news agency TASS, the fire was caused by "the downing of a drone".

Images posted on Telegram by pro-Russian blogger Kirill Fedorov who confirmed it was of the Volna fuel depot fire showed flames and a thick plume of smoke rising over a large tank.

In recent days, Russia and Crimea have been hit by a series of attacks for which Kiev has not claimed responsibility.

Within four days, the explosion of two explosive devices derailed two freight trains near the Ukrainian border, a high-tension line was damaged, and a drone attack caused a massive fire at an oil depot in Crimea.


A "decisive" year

Ukrainian President Volodymyr Zelenskiy said on Wednesday during a surprise visit to Finland that this year would be "crucial" and reiterated his demand for heavy weapons as Ukraine prepares for a counter-offensive against Russian forces.

Zelenskiy told reporters at a joint news conference with his Finnish counterpart Sauli Niinistö: "I think this year will be decisive for us, for Europe and for Ukraine, decisive for victory."

Zelenskiy arrived in Finland on Wednesday for talks with Nordic leaders on supporting his country in Russia's war and relations with Europe, regional governments said.

Finnish President Niinistö's office said he would hold bilateral talks with Zelenskiy, followed by a news conference before attending a regional summit and a second news conference.

The wider summit will be attended by the prime ministers of Sweden, Norway, Denmark and Iceland.

"The summit will focus on Russia's aggressive war on Ukraine, the continued support of Nordic countries for Ukraine, Ukraine's relations with the EU and NATO and Ukraine's initiative for a just peace," Niinistö's office said.

A spokesman for Zelenskiy said in a statement that the Ukrainian government expected the summit to issue a joint statement.

Meanwhile, Berlin's Metropolitan Police are preparing for Zelenskiy's visit in mid-May.

German federal police told Reuters that the Ukrainian president was scheduled to visit the country on May 13 and 14, confirming previous media reports.

For its part, the chancellery has not confirmed Zelenskiy's visit to Berlin so far, and German government spokesman Steffen Hepstrait, asked about reports of Zelenskiy's visit to Berlin, said that the German chancellor's dates are not announced before the Friday before the weekend.