ToplineIran threatened to retaliate against the U.S. after it conducted so-called “self-defense strikes” against Iranian forces on Monday, escalating tensions amid a fragile ceasefire hours after President Donald Trump said negotiations to end the war were “proceeding nicely.” Demonstrators carry a portrait of Iran's Supreme Leader Ayatollah Mojtaba Khamenei after a ceremony to commemorate civilians and military personnel who were killed during military operations involving the United States and Israel, at the Imam Khomeini Grand Mosque in downtown Tehran, Iran, on May 24, 2026. (Photo by Morteza Nikoubazl/NurPhoto via Getty Images)NurPhoto via Getty ImagesKey FactsIran’s foreign ministry said Iran “will not leave any act of mischief unanswered and will not hesitate in defending the country’s integrity” in a statement Tuesday accusing the U.S. of violating the ceasefire.The Islamic Revolutionary Guard Corps also said it “considers its right to retaliate legitimate and definite,” the IRNA state news agency reported Tuesday after the U.S. attacked two Iranian vessels it said were attempting to lay mines in the Strait of Hormuz on Monday and fired on missile-launch sites.The IRGC said it shot down a U.S. drone and engaged a U.S. fighter jet in the crossfire, IRNA reported. Iranian Supreme Leader Mojtaba Khamenei also said Tuesday the U.S. would no longer have “a safe haven for its mischief and for establishing military bases” in the Middle East, calling on Muslim countries to band together to cease serving “as shields for U.S. bases.”The U.S. launched the attacks hours after Trump said on Truth Social that “negotiations with the Islamic Republic of Iran are proceeding nicely,” writing that “it will only be a Great Deal for all or, no Deal at all.”Meanwhile, Secretary of State Marco Rubio said negotiations to end the war would continue in Qatar despite the attacks, echoing Trump’s sentiment that “he’s either going to make a good deal or no deal,” he told reporters during a trip to India. Rubio also said ‘the straits have to be open, they’re going to be open . . . what’s happening there is unlawful, it’s illegal, it’s unsustainable for the world, it’s unacceptable.”TangentTrump called for Saudi Arabia, Qatar, Pakistan and other Middle Eastern countries to sign the Abraham Accords as part of an agreement with Iran to end the war. The agreement, signed at the White House in 2020, established diplomatic relations between Israel and Bahrain and the UAE.Key BackgroundThe strikes Monday stopped short of fully restarting the war, with U.S. Central Command spokesperson Capt. Tim Hawkins telling The New York Times in a statement, “U.S. Central Command Continues to defend our forces while using restraint during the ongoing ceasefire.” The incident is the latest crossfire between the two sides since a ceasefire began on April 7. The last exchange happened on May 8, when the U.S. struck two Iranian-flagged oil tankers as they were entering an Iranian port in the Gulf of Oman, a violation of the U.S. naval blockade against ships coming in and out of Iran. Further ReadingCost Of Iran War Has Increased $4 Billion, Pentagon Says—But Some Estimates Say It’s Closer To $200 Billion (Forbes)Here’s How Many Times The U.S. Has Exchanged Fire With Iran Since Supposed Ceasefire Began (Forbes)Rubio Says ‘Solid’ US-Iran Deal Could Happen ‘Maybe Today’ As Global Markets Rise (Forbes)