More than 100 Ukrainian prisoners of war will be able to return to their families after an exchange of captives of the Russian and Ukrainian armed forces. The swap on Saturday, mediated by the United Arab Emirates, involved 206 military personnel from both countries. Ukraine’s president, Volodymyr Zelenskiy, said that of the 103 Ukrainian “warriors” who were released, 82 were soldiers and privates and 21 were officers, including police officers and border guards. In return for their freedom, Ukraine released more than 100 Russian military personnel taken prisoner in the Kursk border region since Ukrainian forces invaded. It is the second such swap since Ukraine’s incursion into Russia, and occurred after mediated negotiations.

Russian shelling killed at least seven people in four attacks on the south, south-east and east of Ukraine on Saturday, regional Ukrainian governors said. Russian shells struck an agricultural enterprise in the town of Huliaipole, killing three people in the Zaporizhzhia region in south-east Ukraine, governor Ivan Fedorov said. A missile attack in the suburbs of Odesa killed a man and a woman and injured a 65-year-old woman, the Odesa regional governor said. Shelling killed one person in the southern region of Kherson, according to governor Oleksandr Prokudin. In the Kharkiv region, the body of a 72-year-old woman was retrieved from the rubble after Russia struck the village of Pisky-Radkivski, regional governor Oleh Syniehubov said. Details could not be independently verified.

Britain and the US have raised fears that Russia has shared nuclear secrets with Iran in return for Tehran supplying Moscow with ballistic missiles to bomb Ukraine. During their summit in Washington DC on Friday, Keir Starmer, the British prime minister, and the US president, Joe Biden, acknowledged that the two regimes were tightening military cooperation at a time when Iran is in the process of enriching enough uranium to complete its long-held goal to build a nuclear bomb. British sources indicated that concerns were aired about Iran’s trade for nuclear technology, part of a deepening alliance between Tehran and Moscow. However, it’s unclear how much technical knowledge Tehran has to build a nuclear weapon at this stage, or how quickly it could do so. Iran denies that it is trying to make a nuclear bomb.

Iran’s foreign minister said that Tehran was open to diplomacy to solve disputes but not “threats and pressure”, state media reported on Saturday. Abbas Araqchi’s comments came a day after the EU’s chief diplomat said the bloc was considering new sanctions targeting Iran’s aviation sector, in reaction to reports Tehran supplied Russia with ballistic missiles in its war against Ukraine.

Keir Starmer has been urged by former UK defence secretaries and an ex-PM to allow Ukraine to use provided long-range missiles inside Russian territory even without US backing, according to the Sunday Times. The call came from five former Conservative defence secretaries – Grant Shapps, Ben Wallace, Gavin Williamson, Penny Mordaunt and Liam Fox – as well as from Boris Johnson. They warned Starmer that “any further delay will embolden president Putin”, the Sunday Times reported. Starmer and Joe Biden held talks in Washington on Friday on whether to allow Kyiv to use the long-range missiles against targets in Russia. No decision was announced.

Joe Biden will use the remaining four months of his term “to put Ukraine in the best possible position to prevail”, according to the US national security adviser, Jake Sullivan. Biden would meet Volodymyr Zelenskiy in late September at the UN general assembly in New York to discuss aid to Ukraine, Sullivan said. “President Zelenskiy has said that ultimately this war has to end through negotiations, and we need them to be strong in those negotiations,” Sullivan said, adding Ukraine would decide when to enter talks with Russia.

The head of Ukraine’s military intelligence agency, the GUR, Kyrylo Budanov, said North Korean military aid to Russia presented the biggest concern on the battlefield compared with support provided by Moscow’s other allies. “They supply huge amounts of artillery ammunition, which is critical for Russia,” he said, pointing to the ramp up in the battlefield hostilities after such deliveries. Ukraine and the US, among other countries and independent analysts, say the North Korean ruler, Kim Jong-un, is helping Russia in the war against Ukraine by supplying missiles and ammunition in return for economic and other military assistance from Moscow.

Senior Russian security official and former president Dmitry Medvedev said on Saturday that Russia could destroy Ukraine’s capital, Kyiv, with non-nuclear weapons in response to the use of western long-range missiles by Ukraine. Medvedev claimed Moscow already had formal grounds to use nuclear weapons since Ukraine’s incursion into Russia’s Kursk region, but could instead use other weapons technologies to reduce Kyiv to “a giant melted spot” when the Kremlin’s patience runs out.