John Kerry
John Kerry Reuters

US President Donald Trump slammed former Secretary of State John Kerry over reports that Kerry had advised Iranian officials in an attempt to save the Iran nuclear deal, the Joint Comprehensive Plan of Action (JCPOA).

Trump wrote on his Twitter account Monday: "The United States does not need John Kerry’s possibly illegal Shadow Diplomacy on the very badly negotiated Iran Deal. He was the one that created this MESS in the first place!"

Kerry met with Iranian Foreign Minister Mohammed Zarif two weeks ago in an attempt to save the JCPOA, according to a report by the Boston Globe.

President Trump will decide in the coming days whether to remain in the nuclear deal or to withdraw from the agreement.

Kerry has argued that the JCPOA, one of his signature achievements as Secretary of State, remains necessary. He stated that the presentation of Iran's nuclear archive last week by Prime Minister Binyamin Netanyahu, in which Netanyahu proved that Iran's leaders had lied about their nuclear ambitions, showed why the deal must remain in place.

"Every detail PM Netanyahu presented yesterday was every reason the world came together to apply years of sanctions and negotiate the Iran nuclear agreement - because the threat was real and had to be stopped. It's working!" Kerry wrote.