Key events9m agoOpening summaryShow key events onlyPlease turn on JavaScript to use this featureOpening summaryWelcome to the Guardian’s continuing live coverage of the crisis in the Middle East.US forces attacked missile sites in southern Iran and boats trying to lay mines on Monday, US Central Command said, as top Iranian negotiators arrived in Doha for talks to end the war.“US forces conducted self-defence strikes in southern Iran today to protect our troops from threats posed by Iranian forces,” a Centcom spokesperson said. The statement gave no details of the attacks and said only that the targets included missile launch sites and boats trying to “emplace mines”.The strikes threatened an already fragile ceasefire that began on 8 April and came as Iran’s top negotiator and its foreign minister were in Doha for talks with Qatar’s prime minister over the potential deal to end the war, Reuters quoted an official as saying.Meanwhile, Donald Trump said talks with Iran were going “nicely” but warned of fresh attacks if they failed. It “will only be a Great Deal for all, or no Deal at all”, the US president said on social media.The US secretary of state, Marco Rubio, who is in India, said on Tuesday that the strait of Hormuz had to be opened “one way or the other”.“What’s happening there is unlawful, it’s illegal, it’s unsustainable for the world, it’s unacceptable,” he was quoted as telling reporters. Rubio said the negotiating language of the deal with Iran could “take a few days”.In other developments: