A drone attack in southern Russia caused a fire at an oil refinery, the state-run TASS news agency reported on Thursday.

The alleged incident joins a string of recent drone attacks announced by Russia, including what it said was an attempt to assassinate President Vladimir Putin on Wednesday.

The fire at the oil refinery's reservoir, in the southern Krasnodar region's Ilsky settlement, started after an attack by "an unidentified drone", an emergency services official told TASS.

Krasnodar Governor Veniamin Kondratyev said the refinery fire had been localised to a 400-square-metre (4,300-square-foot) area and was quickly extinguished by emergency services.

In the nearby village Volna, a similar blaze at an oil reservoir engulfed 1,200 square metres, with officials blaming a drone crash.

That same day, Moscow said it shot down two drones aimed at Putin's residence and accused Ukraine of attempting a "terrorist act".

Kyiv insisted it had "nothing to do" with the alleged drone attack, suggesting instead it was "staged" by Moscow, while the United States expressed scepticism about any allegations made by Russia.

The spate of apparent sabotage attacks has been used to underscore Russia's exposure to enemy blows as the Kremlin gears up for important anniversary celebrations.

The May 9 victory lap that commemorates the Soviet defeat of Nazi Germany in World War II has become a central event during Putin's rule.

Ukraine's Zelensky in surprise visit to Netherlands

Ukraine President Volodymyr Zelensky arrived at Amsterdam's airport late Wednesday for an unannounced visit to the Netherlands, with a trip to the International Criminal Court on his agenda, local media reported.

Dutch news agency ANP said Zelensky, making his first visit to the Netherlands, landed at Schiphol airport after attending a Nordic summit in Helsinki.

ANP published a dark photo of an aircraft, claiming it was the Dutch government plane probably carrying the Ukrainian leader.

Zelensky will visit the International Criminal Court (ICC), which is based in The Hague, the news agency said.

In March, he issued an arrest warrant for Russian President Vladimir Putin.

The Ukrainian president is also expected to deliver a speech in The Hague entitled "No peace without justice for Ukraine", according to public broadcaster NOS.

A meeting with Dutch MPs is planned, as well as talks with Dutch Prime Minister Mark Rutte, ANP reported, citing unnamed sources.

The Netherlands has pledged both financial and military support to Ukraine since the Russian invasion in February 2022.

The EU nation announced last month that it would buy 14 Leopard 2 tanks with Denmark to give to Kyiv, which is demanding more heavy weapons.

Zelensky made another surprise visit to Finland on Wednesday, promising that this year would be "decisive" in dealing with Russia.

"I believe that this year will be decisive for us, for Europe, for Ukraine, decisive for victory," he told reporters during a joint press conference with his Finnish counterpart Sauli Niinisto.

Zelensky also denied that Ukraine launched an attack on Putin, after Moscow claimed to have shot down two drones launched against the Kremlin compound.

The Dutch government plane that picked up Zelensky flew on Wednesday from a Polish airport to Helsinki, according to NOS.