President Donald Trump said Iran and Israel agreed to a "complete and total" ceasefire on Monday, June 23, hours after Iran claimed it retaliated for the U.S.'s strike on three nuclear sites in the country on June 21. "It has been fully agreed by and between Israel and Iran that there will be a Complete and Total CEASEFIRE (in approximately 6 hours from now, when Israel and Iran have wound down and completed their in progress, final missions!), for 12 hours, at which point the War will be considered, ENDED," Trump wrote on Truth Social. "Officially, Iran will start the CEASEFIRE and, upon the 12th Hour, Israel will start the CEASEFIRE and, upon the 24th Hour, an Official END to THE 12 DAY WAR will be saluted by the World," Trump continued. "During each CEASEFIRE, the other side will remain PEACEFUL and RESPECTFUL." He went on to "congratulate" both Israel and Iran for "having the Stamina, Courage, and Intelligence to end, what should be called, 'THE 12 DAY WAR.'" Israel and Iran have not commented on Trump's statement yet, per CNN and The New York Times. A spokesperson for the Israeli military declined to comment when contacted by the Times. The sudden announcement comes after the U.S.'s strike on three nuclear sites in Iran on Saturday, June 21. Trump first announced the attack on social media, revealing that the U.S. military had "completed our very successful attack on the three Nuclear sites in Iran, including Fordow, Natanz, and Esfahan." Later that evening, Trump addressed the nation from the White House, alongside Vice President J.D. Vance, Secretary of State Marco Rubio and Defense Secretary Pete Hegseth. "Our objective was the destruction of Iran's nuclear enrichment capacity and a stop to the nuclear threat," he said. "Tonight, I can report to the world that the strikes were a spectacular military success. Iran's key nuclear enrichment facilities have been completely and totally obliterated." The president praised the troops involved, adding that while the international conflict "cannot continue," the U.S. believes that Iran has many more viable targets. "If peace does not come quickly, we will go after those other targets with precision, speed and skill," he said. Iran first fired back on Monday, June 23, claiming a “powerful and destructive missile strike on the United States’ Al-Udeid military base in Qatar," NBC News reported. Al-Udeid is the largest U.S. military base in the Middle East. It is the forward headquarters for U.S. Central Command and is home to about 10,000 troops. Explosions were reported near Doha, the capital city of Qatar, where the base is located, and the U.S. Embassy issued a "shelter in place" warning to all citizens. Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer​​, from celebrity news to compelling human interest stories. Trump visited Al-Udeid in May, telling the assembled soldiers, "As president, my priority is to end conflicts, not start them. But I will never hesitate to wield American power if it's necessary to defend the United States of America or our partners. And this is one of our great partners right here." "When we're threatened, America's military will answer our enemies without even thinking about it,” he continued. "You're the people that are defeating chaos, combating terror, defending our interests, supporting our allies, securing our homeland and making America incredibly proud. And, you know what? Making America great again."