(CN) – Department of Homeland Security Secretary Kirstjen Nielsen is leaving her post after 16 months on the job, according to a tweet by the president on Sunday.
The announcement came after Nielsen had a 5 p.m. EST meeting with President Donald Trump at the White House to discuss the U.S.-Mexico border and immigration, administration officials told news outlets.
“Secretary of Homeland Security Kirstjen Nielsen will be leaving her position, and I would like to thank her for her service,” Trump tweeted, announcing that U.S. Customs and Border Protection Commissioner Kevin McAleenan will become acting secretary.
It’s unknown if Nielsen voluntarily resigned or was forced out. Trump is wanting to shake up personnel within the DHS, frustrated over several court challenges to his administration’s immigration policies and the perception that Nielsen wasn’t doing enough to secure the border, according to media reports.
Nielsen often opposed some of the stronger immigration policies supported by senior presidential adviser Stephen Miller. She also defended the administration’s zero tolerance immigration policy that split children from their families at the border and held them in government detention centers.
According to two people familiar with the matter, Nielsen was frustrated by the lack of assistance from other departments to help with the increasing number of families coming across the border.
Border agents apprehended almost 100,000 people in March compared to about 58,000 in January, many of them fleeing from violence in Central America.
Nielsen’s departure comes three days after President Trump withdrew the nomination of Ronald Vitiello for director of Immigration and Customs Enforcement. Her resignation leaves only three women in Trump’s cabinet – Elaine Chao at the Department of Transportation, Betsy DeVos at the Department of Education and Gina Haspel as the director of the CIA.
McAleenan, a career Customs and Border Protection official, spoke out last month about the rise in the number of asylum seekers at the southern border and the strain it has caused his agency.
“That breaking point has arrived this week,” McAleenan said while addressing reporters in El Paso, Texas on March 27. “CBP is facing an unprecedented humanitarian and border security crisis all along our southwest border, and nowhere has that crisis manifested more acutely than here in El Paso.”