O’Brien flew back to Washington on Tuesday from Paris, where he met with French President Emmanuel Macron, to address the attack, which targeted the Departments of Treasury, Commerce, Homeland Security and Defense.

The official said the change in plans is a reflection of how seriously they view the situation. O’Brien has had a heavy travel schedule as a national security adviser and was criticized for travelling to a number of swing states right before the election. He has told friends that he wants to run for president in 2024.

O’Brien will hold National Security Council meetings with his cybersecurity team in the coming days, as well as a likely NSC principals committee meeting in the next few days. The NSC had an emergency meeting on Saturday to discuss the attack.