President Donald Trump announced Saturday morning that “major combat operations” were underway in Iran after U.S. and Israeli forces struck several Iranian military targets as part of Operation Epic Fury.

In a video statement posted at approximately 2:30 a.m. Eastern Time, Trump outlined the objectives of the operation and called on Iranian citizens to overthrow their government once the strikes conclude.

“A short time ago, the United States military began major combat operations in Iran. Our objective is to defend the American people by eliminating imminent threats from the Iranian regime, a vicious group of very hard, terrible people. Its menacing activities directly endanger the United States, our troops our basis overseas and our allies throughout the world,” the president said.

He then recounted a series of historical incidents involving Iran and its proxies, including the 1979 U.S. Embassy takeover in Tehran, the 1983 Marine barracks bombing in Beirut, the 2000 USS Cole attack, and attacks on U.S. forces in Iraq. “For 47 years, the Iranian regime has chanted ‘Death to America’ and waged an unending campaign of bloodshed and mass murder, targeting the United States, our troops and innocent people in many, many countries,” Trump continued.

The president went on to reiterate that the U.S. will not allow Iran to obtain a nuclear weapon. Negotiations on a potential nuclear deal — under which Iran would be forced to give up its enriched uranium supply and submit to international monitoring — were underway throughout the week but ultimately fell through.

“It has always been the policy of the United States, in particular, my administration, that this terrorist regime can never have a nuclear weapon. I’ll say it again. They can never have a nuclear weapon. That is why, in operation midnight hammer last June, we obliterated the regime’s nuclear program at Fordow, Natanz and Isfahan,” Trump said.

“After that attack, we warned them never to resume their malicious pursuit of nuclear weapons, and we sought repeatedly to make a deal. We tried. They wanted to do it. They didn’t want to do it. Again, they wanted to do it. They didn’t want to do it. They didn’t know what was happening. They just wanted to practice evil. But Iran refused, just as it has for decades and decades, they rejected every opportunity to renounce their nuclear ambitions, and we can’t take it anymore.”

The president also acknowledged potential risks of the strikes, including potential U.S. casualties, and appeared to indicate that the military operation will last multiple days.

“This regime will soon learn that no one should challenge the strength and might of the United States Armed Forces. I built and rebuilt our military in my first administration, and there is no military on earth even close to its power, strength or sophistication. My administration has taken every possible step to minimize the risk to U.S. personnel in the region,” Trump continued.

“Even so, and I do not make this statement lightly, the Iranian regime seeks to kill. The lives of courageous American heroes may be lost and we may have casualties. That often happens in war. But we’re doing this, not for now. We’re doing this for the future, and it is a noble mission.”

He then offered prays for American service members and urged Americans to do the same. “We pray for every service member as they selflessly risk their lives to ensure that Americans and our children will never be threatened by a nuclear armed Iran. We ask God to protect all of our heroes in harm’s way, and we trust that, with his help, the men and women of the armed forces will prevail. We have the greatest in the world, and they will prevail.”

In a statement directly to Iranian military forces, Trump urged them to surrender. “To the members of the Islamic Revolutionary Guard, the armed forces and all of the police, I say tonight that you must lay down your weapons and have complete immunity, or in the alternative, face certain death. So lay down your arms. You will be treated fairly with total immunity, or you will face certain death,” he said.

The speech concluded with a direct appeal to the Iranian people. “Finally, to the great, proud people of Iran, I say tonight that the hour of your freedom is at hand. Stay sheltered. Don’t leave your home. It’s very dangerous outside. Bombs will be dropping everywhere. When we are finished, take over your government. It will be yours to take. This will be, probably, your only chance for generations,” Trump declared.