An Army officer assigned to the Defense Intelligence Agency has resigned in protest over the United States’ support for Israel, which he said had “enabled and empowered” the killing of Palestinian civilians.

The officer, Maj. Harrison Mann, announced his resignation and explained his reasons for leaving the service in a post on the social media site LinkedIn on Monday. According to his biography on the site, he has specialized in the Middle East and Africa for about half of his 13-year career and previously served at the U.S. Embassy in Tunis.

“The policy that has never been far from my mind for the past six months is the nearly unqualified support for the government of Israel, which has enabled and empowered the killing and starvation of tens of thousands of innocent Palestinians,” Major Mann wrote in the post, which noted that he had previously emailed his comments to co-workers on April 16. “This unconditional support also encourages reckless escalation that risks wider war.”

Reached by phone on Monday, Major Mann confirmed that he was the author of the post but declined to comment further, referring questions to the D.I.A.’s office of corporate communications.

It is unclear whether other military officers have resigned in protest of U.S. foreign policy since the deadly Hamas-led attacks in Israel in October ignited the war, but the resignation of an active-duty officer in protest of U.S. foreign policy is likely uncommon — especially one in which the officer makes public the reasons for doing so.