President Donald Trump is attacking John Kerry after reports that the former secretary of state has been quietly promoting the Iran nuclear deal, as Trump weighs exiting the controversial landmark accord signed by former President Barack Obama.

Trump says on Twitter 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!”

The Boston Globe reported Friday that Kerry, the lead negotiator on the deal for the Obama administration, had been privately meeting with foreign officials to strategize on how to keep the U.S. in the deal. Trump has been highly critical of the pact and has threatened to exit on May 12.

Kerry has met with Iran’s Foreign Minister Mohammad Javad Zarif. At least one of their meetings was at a June 2017 public event in Oslo, Norway, where they sat on the same panel with EU foreign policy chief Federica Mogherini and extolled the virtues of the nuclear deal.

Kerry, a keen environmentalist who regularly derided climate change skeptics and championed ocean health while secretary of state, has also continued to speak out on those issues since becoming a private citizen.

Last week at an event in Dallas, Trump mocked Kerry over a bicycle accident he had three years ago.

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!

— Donald J. Trump (@realDonaldTrump) May 7, 2018

(AP)