Trump slams 'rogue regime' Iran in national security strategy
His speech followed the release of a 55-page document, which draws from Trump's foreign policy speeches made throughout his first year in office.
In the document, he branded North Korea and Iran as "rogue regimes" which were among the biggest threats to the US administration.
Speaking at the Ronald Reagan International Trade Building, his speech carried his 'America First' slogan which has become more of a guide on how the US will approach the world - and included thinly-veiled criticisms of his predecessors' policies.
"Our leaders engaged in nation-building abroad, while they failed to build up and replenish our nation at home," he said.
"They neglected a nuclear menace in North Korea; made a disastrous, weak, and incomprehensibly bad deal with Iran; and allowed terrorists such as ISIS to gain control of vast parts of territory all across the Middle East."
He added: "To counter Iran and block its path to a nuclear weapon, I sanctioned the Islamic Revolutionary Guard Corps for its support of terrorism, and I declined to certify the Iran deal to Congress."
Trump has been railing against the Iran deal since before he was elected in November last year, calling it "one of the worst" in US history, and warned America could leave it "at any time".
He said during his campaign that Iran was one of the world's "leading state sponsor of terrorism", and said he would deny Iran "all paths to a nuclear weapon".
In October, Trump unveiled an aggressive new strategy towards Iran when he announced he would not re-certify the landmark 2015 nuclear accord.
Signed by Iran, Germany, and UN Security Council permanent members Britain, China, France, Russia and the United States, the JCPOA curbed Iran's nuclear programme in return for sanctions relief.
Since coming to office, Trump has worked to dismantle the legacy of his predecessor Barack Obama on issues ranging from climate change to free trade, often leaving Washington isolated on the world stage.
Agencies contributed to this report.