James Anderson, the acting Under Secretary of Defense, resigned Tuesday, according to two US defense officials, a day after President Donald Trump fired Secretary of Defense Mark Esper, CNN reports.

As the Pentagon's top policy official, Anderson has been the acting Under Secretary of Defense for Policy since June of 2020, following John Rood's termination by the Trump administration in February.

Apparently, Rood and the administration could not come to an agreement on certain policy issues.

It was not immediately clear whether Anderson was asked to step down or voluntarily tendered his resignation.

Anderson has been at the Pentagon since 2018, serving first as the Assistant Secretary of Defense for Strategy, Plans, and Capabilities and later became the Deputy Under Secretary of Defense for Policy before taking over the top policy job upon Rood's ouster.