According to a defense official and another person familiar with the situation, US Defense Secretary Pete Hegseth dismissed the Pentagon's chief planning officer while President Donald Trump considers further strikes against Iran.

According to a defense official, Lt. Gen. Brett Sylvia, who served as the Joint Chiefs of Staff's director for strategy, plans, and policies, or J5, was suddenly fired for alleged "misconduct." He is being investigated for allegedly leaking classified material.

Since Hegseth took over, the Trump administration has made major cuts to the upper echelons of the military, and his departure is the most recent in a long line of senior officers to leave the Pentagon.

In a post on X Thursday morning, Chief Pentagon spokesman Sean Parnell seemed to confirm Sylvia's dismissal and hinted to a probe into purported breaches of secret material, but he offered no further information or proof of possible misconduct.

"The Department took the appropriate personnel action to secure sensitive material after a thorough Air Force OSI investigation. "No further comment will be made regarding the individual or the circumstances of this action to protect the integrity of the investigation," Parnell said in the post, omitting Sylvia's name.

Parnell continued, "This issue and others have been referred to the Justice Department for potential further legal action."

A Justice Department representative stated that the agency "has ongoing investigations related to possible leaks of classified information" in response to a question concerning a prospective probe against Sylvia. The Department of War is one of our government partners with whom we collaborate closely.

A representative for the Air Force Office of Special Investigations confirmed to CNN that they looked into claims that Sylvia had disclosed information without authorization, as detailed in Parnell's article.

Meanwhile, Sylvia's dismissal was verified by a spokeswoman for Joint Chiefs Chairman Gen. Dan Caine. The spokeswoman initially told CNN that Caine and the Joint Staff would like to express their "deepest gratitude" to Sylvia for his 32 years of service and wish him well in the future.

"Upon further review, we determined that the statement did not appropriately reflect the full circumstances" surrounding Sylvia's resignation, the Caine spokeswoman later clarified.

Sylvia has been contacted directly by CNN for comment. Who will assume his duties is unknown.

The Joint Chiefs define the J5 function as a strategic position that advises plans for US participation abroad.

According to the Joint Chiefs website, "The Joint Staff J5 proposes strategies, plans, and policy recommendations to the Chairman of the Joint Chiefs of Staff to support his provision of military advice across the full spectrum of national security concerns to the President and other national leaders and to ensure those recommendations are informed by a larger strategic context –- coordinated with interagency and alliance partners – account for the view and requirements of the combatant commanders – and assess risk in executing the National Military Strategy."

Near the close of the Biden administration, former Defense Secretary Lloyd Austin proposed Sylvia, a former commander of the Army's 101st Airborne Division, for the post.

Sylvia's biography was taken down from the Joint Chiefs website by Wednesday nite.

CNN has reported that Hegseth had strong suspicions that the Joint Staff was leaking information to discredit him and his staff during his time as defense secretary.

Additionally, Hegseth publicly accused three top Pentagon officials of being leakers and fired them last year, including two personal friends who had worked with him for years. Those charges were never validated.

The expulsion of Sylvia occurs at a critical juncture for the Pentagon. US forces in the Middle East are ready to begin fresh, potentially significant military operations against Iran "within 96 hours of receiving" an order from Trump, two US sources told CNN earlier this week.

One of the officials told CNN, "It will be a big effort." Other current and former US officials who are acquainted with internal military planning conversations share this opinion; some claim that the question is not whether Trump will issue a go-order, but rather when. They think it might happen at any point before the year is up, but most likely after the US midterm elections.

Trump hasn't decided what he would do after the midterms, according to officials, but he seems to be leaning toward directing significant action. However, officials also warn that Trump has already shown a tendency to tilt toward particular acts before abruptly changing his mind.

Trump has already declared that there would be no attack prior to the midterm elections on Tuesday.

During Hegseth's time as defense secretary, a number of senior Pentagon officials and officers were fired, including Sylvia. Among them was Army Chief of Staff Gen. Randy George, who was compelled to retire in April one day after Trump hinted that he intended to escalate the conflict with Iran.

In addition, he reportedly intervened in promotions across the military branches, personally influencing leadership, dismissed over two dozen senior commanders, and removed a Navy secretary with whom he disagreed.

According to sources who spoke to CNN at the time, Lt. Gen. Joe McGee, Sylvia's predecessor, also resigned in October 2025 due to pressure from Hegseth. McGee frequently "pushed back" against the defense secretary and Caine on matters ranging from military operations in the Caribbean to Russia and Ukraine.

According to earlier sources, Hegseth was also suspected of leaking against him and not being sufficiently in line with his objectives.