White House national security adviser Tom Bossert will be leaving his position in the administration, according to a White House announcement April 10, 2018.

“The president is grateful for Tom’s commitment to the safety and security of our great country. Tom led the White House’s efforts to protect the homeland from terrorist threats, strengthen our cyber defenses and respond to an unprecedented series of natural disasters. President Trump thanks him for his patriotic service and wishes him well,” White House press secretary Sarah Huckabee Sanders said in a statement.

Bossert, who joined the White House on the first day of the Trump administration, has been at the forefront of many cybersecurity issues, addressing the North Korean-sponsored WannaCry attack and the establishment of international norms in cyberspace.

His departure comes immediately on the heels of John Bolton’s arrival as Trump’s new national security adviser, replacing Lt. Gen. H.R. McMaster, who left the post April 6, 2018.

There is no word yet from the White House about who might replace Bossert.