Vladimir Putin discussed ways to end the crisis in eastern Ukraine with his new Ukrainian counterpart, Petro Poroshenko, on Thursday after Kiev claimed that three tanks had crossed the border from Russia to aid the armed separatists fighting Kiev in the east of the country. Ukraine’s interior minister, Arsen Avakov, said an armoured column, including three tanks, had crossed the border from Russia, adding that part of the column had been destroyed by Ukrainian forces. A number of unverified videos did appear to show tanks in the town of Snizhne, near the border with Russia, and a correspondent said he had seen two tanks in the area. But it was far from clear that they had come from Russia. Rebels in the Luhansk region said they had seized three Ukrainian tanks after engaging government forces close to the city of Luhansk. A spokesman for Poroshenko said the Ukrainian president had told Putin it was unacceptable for the tanks to have crossed into Ukraine. Poroshenko won a clear victory in last month’s presidential election, held several months after the previous president, Viktor Yanukovych, fled the country as protests against his rule peaked. He was sworn into office last weekend, and the first major task is to deal with the uprising in the east of the country, which has led to dozens of deaths over the past two months. A brief statement released by the Kremlin said Poroshenko had “informed Putin of his plans to regulate the situation in Ukraine’s south-east” and added that the Ukrainian leader had wished Putin a happy ‘Russia Day’. June 12 was Russia’s national day, and radio listeners across the country were treated to a live broadcast of a concert from Yalta, part of the Crimea peninsula annexed from Ukraine this year and now functioning as part of Russia. A major concert was also planned for Red Square in Moscow, with patriotic feeling running high after the annexation of Crimea. After losing Crimea, violence broke out in Donetsk and Luhansk regions in eastern Ukraine. Kiev has frequently accused the fighters of being directed from Moscow, a charge which the Kremlin has repeatedly denied, insisting that Russian nationals among the fighters are merely volunteers. Sergei Lavrov, Russia’s foreign minister, said yesterday he believed the rebels were ready for a ceasefire but the initiative should come from Kiev. “We know that the rebels in the southeast are ready to hold fire, but the first step by all rights should be made by the Kiev authorities.” Lavrov also said Russia planned to introduce a UN resolution on the conflict but it would not include the suggestion of Russian peacekeepers being introduced to the region, something the rebels have repeatedly requested.