KYIV, Ukraine (AP) – Prime Minister Fumio Kishida made a surprise visit Tuesday to Kyiv, engaging in duelling diplomacy with Asian rival President Xi Jinping of China, who met in Moscow with Russian President Vladimir Putin to promote Beijing’s peace proposal for Ukraine that Western nations have all but dismissed as a non-starter.

The two visits, about 800 kilometres (500 miles) apart, highlighted how countries are lining up behind Moscow or Kyiv during the nearly 13-month-old war. Kishida, who will chair the Group of Seven summit in May, became the group’s last member to visit Ukraine and meet President Volodymyr Zelenskyy, after paying tribute to those killed in Bucha, a town that became a symbol of Russian atrocities against civilians.

Xi and Putin announced no major progress toward implementing the Chinese peace deal, although the Russian leader said it could be a basis for ending the fighting when the West is ready. He added that Kyiv’s Western allies have shown no interest in that.

US officials have said any peace plan coming from the Putin-Xi meeting would be unacceptable because a cease-fire would only ratify Moscow’s territorial conquests and give Russia time to plan for a renewed offensive.

“It looks like the West indeed intends to fight Russia until the last Ukrainian,” Putin said, adding the latest threat is a British plan to give Ukraine tank rounds containing depleted uranium.

“If that happens, Russia will respond accordingly, given that the collective West is starting to use weapons with a nuclear component,” he said, without elaborating. Putin has occasionally warned that Russia would use all available means, including possibly nuclear weapons, to defend itself, but also has sometimes backed off such threats.

Putin’s comment referred to remarks Monday by UK junior Defense Minister Annabel Goldie, who wrote: “Alongside our granting of a squadron of Challenger 2 main battle tanks to Ukraine, we will be providing ammunition, including armour-piercing rounds which contain depleted uranium. Such rounds are highly effective in defeating modern tanks and armoured vehicles.”

Russian Foreign Minister Sergey Lavrov said the plan shows that the British “have lost the bearings”, and Defense Minister Sergei Shoigu said “it marked another step, and there aren’t so many of them left”.

But weapons expert Hamish de Bretton-Gordon, former commander of Britain’s Royal Tank Regiment, said it was “reckless” of Putin “to try and suggest Britain is sending nuclear material” to Ukraine. He said depleted uranium is a common component of tank rounds, possibly even used by Russia.

“Putin insinuating that they are some sort of nuclear weapon is bonkers,” he told The Associated Press. “Depleted uranium is completely inert. There is no way that you could create a nuclear reaction or a nuclear explosion with depleted uranium.”

Beijing insists it is a neutral broker in Ukraine, and Xi said after his talks with Putin: “We adhere to a principled and objective position on the Ukrainian crisis based on the goals and principles of the UN Charter.” The Chinese plan seeks to “actively encourage peace and the resumption of talks”, he said.

In a joint statement, Russia and China emphasised the need to “respect legitimate security concerns of all countries” to settle the conflict, echoing Moscow’s argument that it sent in troops to prevent the US and its NATO allies from turning the country into an anti-Russian bulwark.

“Russia welcomes China’s readiness to play a positive role in the political and diplomatic settlement of the Ukrainian crisis” and the “constructive ideas” contained in Beijing’s peace plan, the statement said. It added: “The parties underline that a responsible dialogue offers the best path for a lasting settlement…and the international community should support constructive efforts in this regard.”

After meeting Kishida, Zelenskyy told reporters his team had sent his own peace formula to China but hasn’t heard back, adding that there were “some signals, but nothing concrete about the possibility of a dialogue”.

Kishida called Russia’s invasion a “disgrace that undermines the foundations of the international legal order” and pledged to “continue to support Ukraine until peace is back on the beautiful Ukrainian lands”.

Hours before Xi and Putin dined at a state dinner in glittering Kremlin opulence, Kishida laid flowers at a church in Bucha for the town’s victims.

“Upon this visit to Bucha, I feel a strong resentment against cruelty,” he said. “I would like to represent the people in Japan, and express my deepest condolences to those who lost their loved ones, were injured as a result of this cruel act.”

US Ambassador to Japan Rahm Emanuel noted the “two very different European-Pacific partnerships” that unfolded Tuesday.

“Kishida stands with freedom, and Xi stands with a war criminal,” Emanuel tweeted, referring to Friday’s decision by the International Criminal Court to issue an arrest warrant for Putin, saying it wanted to put him on trial for the abductions of thousands of children from Ukraine.

Kyiv’s allies pledged more support. Washington is accelerating its delivery of Abrams tanks to Ukraine, sending a refurbished older version that can be ready faster, the Pentagon announced. The aim is to get the 70-ton behemoths to the war zone by fall.

The Russia-China front against the West was a prominent theme of Xi’s visit. Russia’s Deputy Foreign Minister Sergei Ryabkov accused NATO of seeking to become the world’s dominant military force. “That is why we are expanding our cooperation with China, including in the security sphere,” he said.

Putin is keen to show he has a heavyweight ally and market for Russian energy products under Western sanctions. He and Xi signed agreements on economic cooperation, noting Russian-Chinese trade rose by 30 per cent last year to $185 billion and is expected to top $200 billion this year.

Russia stands “ready to meet the Chinese economy’s growing demand for energy resources” by boosting deliveries of oil and gas, he said, while listing other areas of cooperation, including aircraft and shipbuilding industries and other high-tech sectors.

Whether China will provide military support is a key question. Western officials “have seen some signs” Putin also wants lethal weapons from Beijing, though there is no evidence it has granted his request, NATO Secretary General Jens Stoltenberg said in Brussels.

Further contacts are planned. Xi said he invited Putin to China this year to discuss a regional initiative that seeks to extend Beijing’s influence through economic cooperation.

Both China and Japan have enjoyed recent diplomatic successes that emboldened their foreign policy.