President Vladimir Putin hailed the “return” to Russia of annexed Ukrainian territories, after winning an election slammed as illegitimate by western powers. “Hand in hand, we will move forwards and this will make us stronger … Long live Russia!” Putin told a crowd at a Red Square pop concert to mark 10 years since Russia’s annexation of the Crimean peninsula from Ukraine.

Putin told the crowd that Crimea was the “pride of Russia” and that the Black Sea peninsula had “come back to its native harbour” when Moscow annexed the region. “Through decades, they carried faith in their fatherland. They never separated themselves from Russia and that’s what allowed Crimea to return to our common family,” he said.

A senior Ukrainian official said Putin’s idea of creating a buffer zone inside Ukrainian territory was a clear indication that Moscow planned to escalate the war. Putin raised the possibility of setting up a buffer zone during a speech after winning re-election on Sunday, a move the Kremlin said would be the only way to protect Russia from Ukrainian attacks. “This is … a direct manifest statement that the war will only escalate,” presidential aide Mykhailo Podolyak told Reuters.

Ukrainian President Volodymyr Zelenskiy said it was “critically important” for the US to provide additional military aid to Ukraine, during a meeting with US Republican senator Lindsey Graham on Monday. “The sustained support of Ukraine by international partners, especially the United States, is now more important than ever for the implementation of plans to de-occupy our territories and protect our people,” he said.

Graham said he was confident an aid package stalled by Republican opposition in the US Congress would soon be approved, but called for aid to take the form of a low-interest, waivable loan. He and other Republicans have backed the notion of loans rather than grants for US allies to make the expenditure more sustainable and popular, a plan espoused by former president Donald Trump, the likely Republican candidate in the 2024 presidential election.

Turkey’s President Recep Tayyip Erdoğan on Monday congratulated Putin on his re-election and offered to mediate between Moscow and Ukraine, the Turkish presidency announced. Turkey’s top diplomat, Hakan Fidan, also hit out at “dangerous” rhetoric coming from both Europe and Moscow. “This war must end,” Fidan said in an interview with CNN Turk aired Monday evening. “On both sides, tens of thousands of mothers are burying their children and it’s continuing. Both sides have only too much to lose and nothing to gain,” he said.

EU foreign ministers strongly support taking the revenues from frozen Russian assets to help Ukraine, EU foreign policy chief Josep Borrell said. “I am not saying there was unanimity but [there was] a strong consensus to take this decision,” Borrell told reporters on Monday after a meeting with the ministers held in Brussels.

The Council of the European Union ratified an agreement to increase the EU’s support for the Ukrainian military by 5bn euros ($5.44bn) through a dedicated assistance fund. The EU said the money would fund training and both lethal and non-lethal military gear.

Ukrainian shelling killed four people near Russia’s border city of Belgorod on Monday, bringing the total number of dead in the region since last week to 15, authorities said. “Four people were killed in the village of Nikolskoye as a result of a direct shell hit on a private residential house,” governor Vyacheslav Gladkov said.

Ukrainian officials said Monday that Russia had launched missiles on border regions where it has intensified attacks in recent days. Overnight, Russia launched five missiles on the north-eastern Kharkiv border region and also targeted the neighbouring Sumy border region with two missiles, the Ukrainian air force said. Russia also launched 22 drones on Ukraine overnight, 17 of which were shot down in various regions, the air force said.