As the conflict enters its 503rd day, these are the main developments.

Fighting

• Ukraine said its forces made a “definitive advance” on the southern flank of Bakhmut as the country continues its counteroffensive against occupying Russian troops. Deputy Defence Minister Hanna Maliar added that “on the northern flank of the battle there are no changes of positions”.
• The Russian Defence Ministry, meanwhile, said its forces had repelled Ukrainian attacks in three areas of Ukraine’s eastern Donetsk region, including Klishchiivka, the focus of fighting in recent days near Bakhmut. The ministry also said Russian forces thwarted Ukrainian attacks in the south, including near the village of Rivnopil, which Ukrainian forces said they captured two weeks ago.
• Yuriy Malashko, governor of Zaporizhia region, said Russian missiles struck an aid distribution centre set up in a school in the village of Orikhiv, killing seven people and injuring 11. The General Prosecutor’s office said the incident was being investigated as a war crime.
• The United Kingdom’s defence ministry said Russia was “almost certainly struggling with a crisis of combat medical provision”. The analysis said Russia had been suffering an average of about 400 casualties a day since the war began in February 2022.
• An independent statistical analysis of Russia’s war dead found nearly 50,000 Russian men have died since Moscow launched its full scale invasion. Two independent Russian media outlets, Mediazona and Meduza, working with a data scientist from Germany’s Tübingen University, used Russian government data to shed light on one of Moscow’s closest-held secrets.

Wagner fallout

• The Kremlin said Russia’s President Vladimir Putin held talks with Wagner Group boss Yevgeny Prigozhin in Moscow, five days after the mercenary chief led an armed mutiny in Russia.

Diplomacy

• Turkish President Recep Tayyip Erdogan agreed to back Sweden’s bid to join NATO after a year of blocking the move in what NATO Secretary-General Jens Stoltenberg described as an “historic day“.
• Ukrainian President Volodymyr Zelenskyy urged NATO leaders to “confirm” his country’s membership of the alliance at its annual summit, which gets under way in Vilnius on Tuesday. Earlier, Foreign Minister Dymytro Kuleba, said NATO members have reached a consensus on removing the requirement for Kyiv to follow a membership action plan ahead of the summit, which he said would shorten Ukraine’s “path to NATO”.
• A spokesman for UK Prime Minister Rishi Sunak said the prime minister wanted to work with allies to discuss a “pathway” for Ukraine to join NATO, but the exact mechanism was up for discussion. The spokesman was speaking after Sunak held talks with US President Joe Biden.
• German Chancellor Olaf Scholz said “Israel style security guarantees” for Ukraine will be among the key topics for discussion in Vilnius.
• Talks between Putin and Erdogan, remain the “only hope” to extend the Black Sea grain deal that is set to expire next week, Russia’s state news agency RIA Novosti reported. The original agreement was brokered between Russia and Ukraine by the United Nations and Turkey in July 2022, and aimed to prevent a global food crisis by allowing Ukrainian grain trapped by Russia’s invasion to be safely exported from Black Sea ports.
• Poland said it arrested a Ukrainian citizen suspected of spying for Russia. “The suspect kept surveillance of military facilities and seaports. He was systematically paid by the Russians,” said Interior Minister Mariusz Kaminski.

Weapons

• The US defended its decision to supply controversial cluster munitions to Ukraine. State Department Spokesperson Matthew Miller said they would serve as a “bridge” to sustain Ukrainian firepower while the US ramps up production of conventional artillery.
• An investigation by multiple European media outlets found that more than a year into the war, the European Union and Ukraine have yet to step up the production of ammunition. Ukraine’s Kyiv Independent, Dutch-based Lighthouse Reports and Follow the Money, Spain’s El Diario, Estonia’s Delfi and France’s Libération conducted the investigation. It found that EU governments had signed hardly any long-term contracts with producers while Ukraine’s arms makers had complained about a lack of state support to scale up production.
• A senior government official said Germany was expected to make an announcement on the delivery of military hardware to Ukraine over the course of the week’s NATO summit.