“Our foreign policy is a complete disaster," said the billionaire businessman during his speech at Washington’s Mayflower Hotel Wednesday, according to presstv.ir.
Trump attacked President Barack Obama as he believed he gave Tehran a “great power.”
“He has treated Iran with tender love and care and made it a great power in the Middle East – all at the expense of Israel, our other allies in the region and, critically, the United States,” Trump said. "We're rebuilding other countries while weakening our own."
Iran and the five permanent members of the UN Security Council – the United States, France, Britain, China and Russia – plus Germany signed the agreement on July 14, 2015 following two and a half years of intensive talks.
The controversial GOP hopeful also attacked the Obama administration by picking on US allies like, Japan and South Korea.
"Our allies are not paying their fair share," he warned. "The countries we are defending must pay for the cost of this defense. And if not, the US must be prepared to let these countries defend themselves."
"'America First' will be the major and overriding theme of my administration," Trump told supporters, co-opting the slogan of America's pre-World War II isolationists.
The business mogul became notorious particularly for offensive remarks against Muslims, Hispanics, and women in the run-up to the 2016 presidential election.