BEIRUT, Lebanon — An investigative team with the international group that monitors compliance with the chemical weapons ban accused the Syrian government on Wednesday of having launched three chemical weapons attacks on one village in northern Syria in March 2017, sickening scores of people.

The team, established by the Organization for the Prohibition of Chemical Weapons, said in a report that in the span of one week, Syrian fighter jets had twice dropped bombs containing sarin nerve agent on the village and a helicopter had targeted its hospital with a cylinder containing chlorine.

Reports of chemical weapons use have surfaced frequently during Syria’s nine-year civil war, and officials from the United States, Turkey and other countries have accused the Syrian government of using banned weapons to try to break the back of the rebel movement that is seeking to oust President Bashar al-Assad.

The O.P.C.W. verified the use of chemical weapons in many of these cases, but had refrained from assigning blame for who deployed them, raising criticism from activists that holding back such judgments diminished the chances for accountability.