Vladimir Putin orchestrated the killing of Wagner mercenary boss Yevgeny Prigozhin thanks to his own weakness, Ukraine’s President Volodymyr Zelensky has said. The Ukrainian president made the off-hand remark during a conference in Kyiv on Friday, without providing any additional evidence. Mr Prigozhin died in an unexplained crash when a plane carrying himself and some of his top lieutenants went down when flying between Moscow and St Petersburg in late August. Mr Prigozhin offered the most severe challenge to the Russian president’s authority in more than 20 years in power when he and his Wagner fighters rose up against Moscow in June. The mutiny began when Mr Prigozhin’s forces left their base in southern Russia and marched on Moscow. It prompted the Kremlin chief to accuse Mr Prigozhin of "treason" and a "stab in the back". Mr Prigozhin and his troops were eventually halted 24 hours later, about 125 miles from the Russian capital, when a deal was brokered between the Kremlin and Mr Prigozhin by the Belarusian president, Alexander Lukashenko. See our live blog for the latest developments in Ukraine Mr Prigozhin had been in a public feud with Russian defence minister Sergei Shoigu and chief of the general staff Valery Gerasimov for months about the direction of Russia’s invasion of Ukraine, which is now in its 18th month. There has been a crackdown on dissent against the war across Russian society, with dozens facing prison sentences. Western leaders have suggested that little of note happens in Russia without Mr Putin’s sign-off and that he would be unlikely to let the embarrassment of the mutiny go without sending a message to others looking to undermine his presidency. Mr Zelensky said on Friday: "The fact that he killed Prigozhin - at least that’s the information we all have, not any other kind - that also speaks to his rationality, and about the fact that he is weak.” He made the statement in answer to another question about the Russian president. The Kremlin says all possible causes of the crash will be investigated, including the possibility of foul play. It has called the suggestion that Putin ordered the deaths of Mr Prigozhin and his men an "absolute lie". Many critics of Mr Putin have died in unclear circumstances during his 23 years in power, or narrowly escaped dying. Russia’s most recognisable opposition figure, Alexei Navalny, is facing decades in prison over various charges that are widely considered to be politically motivated. He was arrested in 2021 upon returning to Moscow after recuperating in Germany from what is believed to have been nerve agent poisoning. He has blamed that poisoning on the Kremlin, as did a number of Western nations. The Kremlin has denied involvement. Meanwhile, Mr Zelensky’s hometown Kryvyi Rih was one of several sites in Ukraine to be hit by Russian missiles overnight into Friday. Three people were also killed after a Russian bomb struck the village of Odradokamianka in the Kherson region of southern Ukraine. The strikes come as Ukraine is trying to push back Russian troops and reclaim its territory as part of a summer offensive. However, Mr Zelensky said that his nation is finding it harder and slower to secure sanctions on Russia and weapon supplies to help fend off Moscow's forces. He said Ukraine's three-month-old counteroffensive would make faster gains in the south and east if Kyiv's military received more powerful weapons. "The war is slowing down. This is true, we recognise this. All the processes are becoming harder and slowing down: from sanctions to the delivery of weapons," he said. Read More Wagner Group set to be declared a terrorist organisation The UK says it will declare Russia’s Wagner mercenary group a banned terrorist organization Wagner to be declared a terrorist organisation, Home Office says Sunak pledges to ‘put pressure’ on Moscow as he arrives in India for summit Cuba arrests 17 for allegedly helping recruit some of its citizens to fight for Russia in Ukraine Ukraine-Russia war – live: Four dead as Putin’s forces strike Zelensky’s hometown and Kherson