 Ships carrying Ukrainian grain awaited inspection in Turkey's Bosphorus on May 10 as the Black Sea grain deal which allowed Ukrainian exports via the Black Sea was in danger of collapsing. Four-way talks on the deal between Russia, Ukraine, Turkey and the United Nations are due to take place in Istanbul this week, as Russia threatened to quit on May 18 over obstacles to its own grain and fertilizer exports. The inspection of vessels by the United Nations resumed on May 9, after the United Nations said no ships were inspected on Sunday or Monday. The UN in Turkey brokered the Black Sea export agreement in July to help tackle a global food crisis that has been worsened by Moscow's war in Ukraine. Officials from Russia, Ukraine, Turkey and the UN make up a joint coordination center in Istanbul, which implements the deal.