Iran has promoted a hard-line ex-commander as its top security official, shaking up its highest decision-making body on national defense after saying it was “very close” to a deal with Oman over shipping through the Strait of Hormuz.

Mohsen Rezaee was appointed the new leader of the Supreme National Security Council, the state-run Islamic Republic News Agency reported late Sunday. He replaces Mohammad Bagher Zolghadr, a fellow hard-liner who accepted a new position as political adviser to the country’s supreme leader.

It’s unclear what the reshuffle means for diplomacy, with U.S. President Donald Trump making periodic threats of escalation as he pushes for a resolution with Iran that would allow traffic to move freely through the Strait of Hormuz. Rezaee, a former commander of the Islamic Revolutionary Guard Corps, has been a key figure in Iran’s security apparatus for years and previously advocated for advancing Iran’s nuclear program.