GENEVA — United Nations investigators added their voices on Wednesday to a mountain of evidence of the Syrian military’s responsibility for a chemical attack on a rebel-held town five months ago that left villagers foaming at the mouth and gasping for breath.

A United Nations Commission of Inquiry monitoring the six-year conflict in Syria said that Sukhoi 22 aircraft operated by the Syrian Air Force carried out the attack on the village of Khan Sheikhoun early on April 4. It killed at least 83 people, injured close to 300 others and prompted President Trump to order dozens of cruise missile strikes on the airfield from which the jet fighters had launched their attack.

The panel’s findings are the first authoritative statement to pin responsibility for the attack unequivocally on the Syrian government.

Although a number of foreign governments, watchdogs and news organizations, including The New York Times, had concluded that Syrian forces were most likely behind the attack, the latest report — released by a body tasked with investigating violations by all sides in the conflict — carries more weight and will be harder for the Syrian government and its allies to dismiss as politicized.