Iran’s Islamic Revolutionary Guard Corps announced Tuesday (May 26) it had shot down a US MQ-9 drone, a day after the US launched strikes in “self-defence” on southern Iran, targeting missile launch sites and Iranian boats to place mines.The US attack marked the latest escalation despite the fragile ceasefire brokered on April 8. The two countries have held multiple rounds of talks in a bid to end the war.The US Central Command (CENTCOM) justified the strikes, saying they were designed “to protect our troops from threats posed by Iranian forces”. The US has accused the Iranian military of laying mines near the Strait of Hormuz, through which a fifth of global oil and gas passes in normal times.“Targets included missile launch sites and Iranian boats attempting to emplace mines,” Navy Captain Tim Hawkins, a CENTCOM spokesperson, said in a statement on Monday. “US Central Command continues to defend our forces while using restraint during the ongoing ceasefire,” CENTCOM said, without providing further details.In response, the IRGC said that Iran reserved the “legitimate and definite” right to retaliate against any ceasefire violations by the United States. Iran’s Supreme Leader, Mojtaba Khamenei, took to Telegram to say that the US would no longer have a safe haven in the Middle East, and that Gulf powers would no longer be a shield for US bases.The attacks came even as progress was being made towards a deal to reopen the Strait of Hormuz.On Monday, Iran said that while some progress had been reached in talks with the US, a deal with the US “is not imminent”. Both parties said they have made progress on a memorandum of understanding (MoU) focused on ending the war and the US naval blockade, in exchange for Iran permitting safe transit through the Strait of Hormuz, according to Esmaeil Baghaei, Iranian foreign ministry spokesperson.Story continues below this adAlso Read | Quad foreign ministers meet in Delhi today: What is the Quad and what are its objectives?The MoU reportedly entails a 60-day ceasefire extension, during which time further negotiations would be held over Iran’s nuclear programme.Japanese newspaper Nikkei cited a Middle East diplomatic source who said the plan to open the Strait of Hormuz about 30 days after the two reach a deal to end hostilities. During this window, Iran would clear mines from the strait, and ships would be able to navigate freely and safely, with Iran stopping the collection of transit fees, Nikkei said.Iran’s nuclear programme still a thorny issueTalks to normalise relations and ensure a continued ceasefire have been stonewalled by US President Donald Trump’s resistance to Iran’s continued possession of enriched uranium, or its potential to make nuclear weapons. The US wants Iran to suspend its nuclear programme for 20 years and surrender its 972-pound stockpile of highly enriched uranium. Iran has repeatedly rejected such proposals.Contrasting signals continue to emerge: a senior US official anonymously told Reuters that Iran had agreed “in principle” to open the Strait of Hormuz, in exchange for the US lifting its naval blockade and to dispose of Iran’s highly enriched uranium, a long-standing demand of Trump.Story continues below this adNewsletterFollow our daily newsletter so you never miss anything important. On Wednesday, we answer readers' questions.SubscribeIran presented a different picture, with senior Iranian diplomat Hossein Nooshabadi telling Iran’s ISNA news agency that it had made no commitments on its nuclear programme. He added that the possible framework deal included the end of war on all fronts, including Lebanon, the release of blocked Iranian assets, lifting the US naval blockade, and reopening the Strait of Hormuz, the withdrawal of US forces from Iran’s vicinity, and freeing up Iran to sell oil.US Secretary of State Marco Rubio, in India as part of the Quad Foreign Ministers meeting, on Tuesday said that negotiating a deal with Iran “could take a few days”. On the strikes, he said the Strait of Hormuz needed to be open “one way or the other”. However, he said a deal was still possible ahead of talks between Iran and Qatar, which has now stepped in as mediator.