Ukrainian president Volodymyr Zelensky said Russian troops were holding the Zaporizhzhia nuclear plant “hostage” and its safety could not be guaranteed until they left it.

Russian troops have occupied the nuclear power plant, Europe’s largest, since March last year, shortly after Vladimir Putin waged the unprovoked war in Ukraine.

“Holding a nuclear power station hostage for more than a year – this is surely the worst thing that has ever happened in the history of European or world-wide nuclear power,” Mr Zelensky said in his nightly video address.

He added that Russia was using it for “radiation blackmail”.

An ally of Vladimir Putin has warned that Russia has the weapons to destroy any enemy, including the United States, if its own existence is threatened.

The comments from Nikolai Patrushev, the influential secretary of Russia’s Security Council, are the latest from a senior Russian official to raise the spectre of a nuclear showdown between the world’s two largest nuclear powers, something Moscow says it wants to avoid.

“American politicians trapped by their own propaganda remain confident that, in the event of a direct conflict with Russia, the United States is capable of launching a preventive missile strike, after which Russia will no longer be able to respond. This is short-sighted stupidity, and very dangerous,” Mr Patrushev told the state Rossiiskaya Gazeta newspaper on Monday.

“Russia is patient and does not intimidate anyone with its military advantage. But it has modern unique weapons capable of destroying any adversary, including the United States, in the event of a threat to its existence”, he said.

Germany has delivered 18 Leopard battle tanks to Ukraine, chancellor Olaf Scholz said on Monday.

The delivery of the “very modern” German-made battle tanks comes some two months after Berlin finally gave the green light for them to be sent.

Ukraine has appealed to its Western allies to send the heavy weaponry required to push back Russian forces, ahead of a possible spring counter-offensive by Kyiv.

“Yes, we delivered Leopard tanks as we announced,” Mr Scholz told a press conference with Dutch prime minister Mark Rutte in Rotterdam.

The Russian navy has fired supersonic anti-ship missiles at a mock target in the Sea of Japan, the defence ministry said today.

“In the waters of the Sea of Japan, missile ships of the Pacific Fleet fired Moskit cruise missiles at a mock enemy sea target,” the ministry said in a statement.

“The target, located at a distance of about 100 kilometres, was successfully hit by a direct hit from two Moskit cruise missile.”

Belarus has accused Poland of causing long delays at its border with the European Union by slowing the movement of trucks, alleging that Warsaw was failing to implement bilateral agreements.

Poland, a fierce critic of veteran Belarusian leader Alexander Lukashenko, in February closed one of its key border crossings with Belarus, citing security concerns – a decision Minsk called “catastrophic”.

“Since Friday, a queue in front of the only accessible border crossing point on the Belarusian-Polish border … has doubled in size and now totals 1,000 vehicles,” the Belarusian border committee said in a statement.

“The main reason is the failure of the Polish side to implement bilateral agreements on the passage of trucks,” it said, accusing Poland of only processing 61 per cent of the typical number of trucks crossing the border over the weekend.

Ukraine’s top security official has denounced the Kremlin’s plans to station tactical atomic weapons in Belarus, saying that Russia was taking its ally as a “nuclear hostage”, reports Karl Ritter.

Oleksiy Danilov, the secretary of Ukraine’s National Security and Defense Council, warned on Sunday that Putin’s announcement was “a step towards internal destabilisation” of Belarus that maximised “the level of negative perception and public rejection” of Russia and Putin in Belarusian society.

The Kremlin, Mr Danilov added, “took Belarus as a nuclear hostage.”

In case you missed it, our world affairs editor Kim Sengupta wrote last week that the presence of China’s Xi Jinping in Moscow, and the Japanese prime minister Fumio Kishida in Kyiv, had “illustrated the global impact of this conflict in the heart of Europe, with old strategic alliances being strengthened and new ones being formed”.

You can read his analysis in full here:

Ukraine’s ambassador to Switzerland has said she expects the nation to change its mind on blocking re-exports of arms to Ukraine – despite its longstanding foreign policy of neutrality.

An opinion poll published by the Sotomo Institute in Zurich in late January found that 55 per cent of respondents favoured re-exporting Swiss-made war materiel to Ukraine.

Speaking to Reuters, ambassador Iryna Venediktova said she expected Switzerland to change its position very soon as support for the re-export of Swiss arms to her country increases.

“We need these weapons and ammunition as fast as possible,” she said. “It is a question of survival of our people, our nation, our state.”

Switzerland’s tradition of neutrality should not include blocking re-exports of Swiss weapons to Ukraine, Kyiv’s ambassador has insisted, claiming the “whole world expects a fair position” instead.

Switzerland’s government reiterated this month it would not change its long-standing policy of banning any country that buys Swiss arms from sending them to the party of a conflict.

But speaking to Reuters at the Ukrainian embassy in Bern, Iryna Venediktova said neutrality and the re-export of arms to Ukraine should be viewed as separate issues.

“I respect Swiss neutrality because it is a pillar of the Swiss state,” she said. “But every day I stress that neutrality and re-export are two absolutely different terms.”

“We don’t ask, ‘Give your weapons to us directly.’ We just ask not to block [re-exports] … not to contribute to this crime of aggression,” Ms Venediktova said. “The whole world is watching, and the whole world expects a fair position, nothing more than a fair position.”

Switzerland has denied requests from Germany, Denmark and Spain to re-export Swiss war materiel to Ukraine. Switzerland, however, has adopted the European Union’s sanctions against Russia over the invasion, which it has repeatedly condemned.