Ukraine engages in large-scale operation as Russia drops bombs and shells during Zelensky's visit.

Russia has blamed Ukraine for an attack in the border town of Belgorod, while Ukraine denies the allegations and accuses two armed Russian opposition groups of being responsible. Ukrainian President Volodymyr Zelenskyy visited troops on the front line in Donetsk. Hungary's Viktor Orban has said Ukraine's troops are unlikely to win the war against Russia. The Ukrainian port of Pivdennyi has halted operations due to Russia not allowing ships to enter it. Poland and Germany are ready to train Ukrainian pilots to fly F-16 fighter jets. European Union countries have sent 220,000 artillery shells and 1,300 missiles to Ukraine. Former Russian President Dmitry Medvedev has warned against sending more arms to Ukraine, saying it increases the risk of a "nuclear apocalypse".