Rob Joyce, the White House cybersecurity coordinator, has announced he will return to the National Security Agency.

Joyce’s announced departure comes on the heels of the resignation of White House homeland security adviser Tom Bossert, and a number of other National Security Council officials. President Trump’s new national security adviser, John Bolton, began in the job last week, replacing H.R. McMaster.

Joyce, a career federal employee, will stay on as needed to facilitate the transition to his eventual replacement, White House officials said. He is currently also serving as the acting deputy homeland security adviser, which includes coordinating responses to natural disasters and monitoring terrorism threats.

Joyce, who was detailed to the White House from the NSA at the start of the Trump administration, has served more than 25 years at the spy agency. There, he held various leadership positions. He headed the elite hacking or “offensive” division, called Tailored Access Operations, which penetrated networks overseas to gather foreign intelligence.

He has also led the Information Assurance Directorate, which handled cybersecurity or defense of classified government networks. Both divisions have been folded into the agency’s new directorate of operations.

“Serving as the White House’s cybersecurity coordinator for the last 14-months has been a tremendous opportunity to work on some of our nation’s most important cyber challenges,” Joyce said in a statement. “I look forward to continuing to serve our nation at the agency I’ve called home for the last 27 years.”

It is not clear what position he will return to, nor who will succeed him at the White House. Joyce brought a wealth of operational experience to the job, having worked in cyber offense and defense at the NSA.

As cybersecurity coordinator, he advocated for stronger actions to hold foreign adversaries accountable for malicious acts in cyberspace. On his watch, the Trump administration has publicly blamed North Korea and Russia for illicit hacking activities and alerted the nation that Russia was targeting the U.S. energy sector with malware that could potentially be used for sabotage.