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US Homeland Security Secretary Kirstjen Nielsen resigned on Sunday. Her letter of departure read that the United States deserves, “to have all the tools and resources they need to execute the mission entrusted in them”. The abrupt departure came after Nielsen met with President Donald Trump, who recently decided to drop border official Ron Vitiello’s nomination to lead US Immigration and Customs Enforcement.

It's the latest signal that the president plans to take the department in a new direction. The White House is reportedly discussing new steps to slow the flow of migrants, including bringing back a version of separating migrant families at the border. Another option on the table: ramping up deportations of immigrants already living in the United States illegally who have an outstanding order of removal.

Speaking to reporters in the Oval Office on Tuesday, Trump said he is not looking to reinstate the controversial family separation policy he suspended last year, but then implied it was an effective means of stemming unauthorised border crossings.