Here are the key quotes from Trump during his address from the White House:
"The Iran deal is defective at its core. If we do nothing, we know exactly what will happen. In just a short period of time, the world's leading state sponsor of terror will be on the cusp of acquiring the world's most dangerous weapons.
"Therefore, I am announcing today that the United States will withdraw from the Iran nuclear deal."
"The fact is this was a horrible, one-sided deal that should have never, ever been made. It didn't bring calm, it didn't bring peace, and it never will."
"At the heart of the Iran deal was a giant fiction that a murderous regime desired only a peaceful nuclear energy program. Today, we have definitive proof that this Iranian promise was a lie."
State sponsor of terror
"The Iranian regime is the leading state sponsor of terror. It exports dangerous missiles, fuels conflicts across the Middle East, and supports terrorist proxies and militias such as Hezbollah, Hamas, the Taliban, and Al-Qaeda."
"In a few moments, I will sign a presidential memorandum to begin reinstating US nuclear sanctions on the Iranian regime. We will be instituting the highest level of economic sanction. Any nation that helps Iran in its quest for nuclear weapons could also be strongly sanctioned by the United States."
Senior aides to Trump later specified that companies would have 90 to 180 days to "wind down" business in Iran or face punitive measures.
"As we exit the Iran deal, we will be working with our allies to find a real, comprehensive, and lasting solution to the Iranian nuclear threat.
"This will include efforts to eliminate the threat of Iran's ballistic missile program; to stop its terrorist activities worldwide; and to block its menacing activity across the Middle East."
"America will not be held hostage to nuclear blackmail. We will not allow American cities to be threatened with destruction. And we will not allow a regime that chants 'Death to America' to gain access to the most deadly weapons on Earth."
"It has now been almost 40 years since this dictatorship seized power and took a proud nation hostage."
"But the future of Iran belongs to its people. They are the rightful heirs to a rich culture and an ancient land. And they deserve a nation that does justice to their dreams, honor to their history, and glory to God."
Ready to renegotiate
"They are going to want to make a new and lasting deal, one that benefits all of Iran and the Iranian people. When they do, I am ready, willing, and able."
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)