Kirstjen Nielsen: US Homeland Security chief resigns bbc.com

The US Secretary of Homeland Security Kirstjen Nielsen, who enforced some of President Trump's controversial border policies, has resigned. Ms Nielsen called it "an honour of a lifetime" to work in the department. President Trump tweeted she would be temporarily replaced by Customs and Border Protection Commissioner Kevin McAleenan. Ms Nielsen was responsible for implementing the proposed border wall and the separation of migrant families.