Donald Trump speaks at a meeting in the White House on 4 April 2019

Donald Trump has labelled Iran’s Revolutionary Guard Corps a terrorist organisation in an unprecedented move that could have lasting consequences for the United States.

The president declared for the first time in history that another government entity was a terror group, potentially making it more difficult for American diplomats and other officials working in the region.

The move arrives a day after the president accepted of Homeland Security secretary Kirstjen Nielsen, with whom he has repeatedly clashed over his administration’s more hardline immigration policies, as he seeks more drastic action to address the “crisis” at the US southern border.

Ms Nielsen's departure on Sunday was followed by the resignation of Randolph Alles, who was in charge of the Secret Service but had apparently fallen out of Mr Trump's good graces weeks ago.

Those two resignations were expected to be followed by more departures in the Department of Homeland Security in the days or weeks to come as a part of a phase that some in the media have begun to call a purge.

Criminals who worked for Trump Show all 5 1 /5 Criminals who worked for Trump Criminals who worked for Trump Michael Cohen Former lawyer for Donald Trump was sentenced to three years in prison on counts involving evading income tax, false disclosure of the hush money paid to Stormy Daniels and another hush money charge Getty Criminals who worked for Trump Paul Manafort Former campaign manager for Trump Manafort was found guilty in February 2018 of five counts of tax fraud, two counts of bank fraud and one count of failure to disclose a foreign bank account. The crimes occurred prior to his appointment in Trump's campaign Getty Criminals who worked for Trump George Papadopoulos Former Trump campaign adviser Papadopoulos pleaded guilty to lying to the FBI in October 2017. He had lied about making contact with a professor who claimed that the Russians had dirt on Hillary Clinton. He was sentenced to 14 days in jail Getty Criminals who worked for Trump Michael Flynn Former White House National Security adviser Michael Flynn pleaded guilty to lying to the FBI in December 2017. He had lied about conversations that he had with the Russian ambassador to the US during Trump's Presidential campaign. He was not given prison time due to his "significant assistance" to the Mueller investigation Getty Criminals who worked for Trump Rick Gates Deputy chairman of Trump's presidential campaign Gates pleaded guilty to lying to the FBI in February 2018 AFP/Getty

Also in the news was Devin Nunes, the ranking Republican on the House Intelligence Committee, who made eight criminal referrals to the attorney-general, William Barr, over the leaking of Mr Trump’s phone calls with ex-Australian prime minister Malcolm Turnbull and former Mexican president Enrique Pena Nieto and national security adviser Michael Flynn’s calls to a Russian ambassador.

Coming up this week, attorney general William Barr is slated to testify before both the House and the Senate on his department's budget for the coming year.

But, that testimony is likely to veer of track a bit as democrats grill him about the contents of the Mueller report, which he received last month.

Mr Barr as pledged to send the report to Congress in the coming weeks, but it remains to be seen just how much of the report might be redacted.