“They are going to be such a wealthy, such a powerful nation,” Trump said in an interview with NBC News on Sunday.
He further claimed, “They are going to have nuclear weapons. They are going to take over parts of the world that you wouldn't believe.”
Trump added, “Iran is going to be unbelievably rich and unbelievably powerful and Israel is in real trouble.”
He also described US Secretary of State John Kerry and other American negotiators of the agreement as “incompetent”.
The front runner presidential candidate said, however, that he will abide by the "deal" if elected president.
Iran and the Group 5+1 (Russia, China, the US, Britain, France and Germany) finalized the text of lasting deal on Tehran’s nuclear program on July 14.
While the United Nations Security Council has adopted a resolution to endorse the deal, the text of the document needs to be ratified by both Iran's Parliament and the US Congress.
US President Barack Obama has promised a swift veto in the event of a Congress rejection of the agreement in September. Lawmakers would then have to find enough votes to override the president. 20 of 46 Senate democrats have so far supported the deal and Obama administration only needs 13 more votes to defeat a veto override.