Donald Trump
Donald TrumpReuters

US President Donald Trump accused Iran of being in "total violation" of the 2015 nuclear agreement and warned that the US would soon substantially increase sanctions on the Islamic Republic.

"Iran has long been secretly “enriching,” in total violation of the terrible 150 Billion Dollar deal made by John Kerry and the Obama Administration. Remember, that deal was to expire in a short number of years. Sanctions will soon be increased, substantially!" Trump tweeted.

The president's warning follows Iran's announcement that it would expand its uranium enrichment beyond the 3.67% limit permitted in the deal.

Trump said in response to the move, “Iran better be careful, because you enrich for one reason, and I won’t tell you what that reason is, but it’s no good. They better be careful.”

The President told reporters that "Iran's doing a lot of bad things" but also vowed they "will never have a nuclear weapon.”

Tensions have exacerbated since Iran shot down a US drone, claiming it violated Iranian airspace near the Strait of Hormuz.

Trump approved military strikes against Iran in retaliation for the downing of the drone, but pulled back from launching them. He later made clear that he had not called off the planned strike on Iran but rather simply stopped it from going forward at that time.