The Trump administration is imposing economic sanctions on a Chinese state-owned oil trading company and its top executive for buying Iranian oil in violation of an American ban, Secretary of State Mike Pompeo said Monday.

Mr. Pompeo said in a foreign policy speech at a veterans’ convention in Florida that the company, Zhuhai Zhenrong, and its chief executive, Li Youmin, were “violating U.S. restrictions on Iran’s oil sector.” It is the first time the Trump administration has penalized a Chinese company and executive for defying recent United States sanctions on Iranian oil exports.

The move is certain to increase tensions between Washington and Beijing, which are embroiled in a long-running trade war and a strategic competition that spans the globe.

It is also certain to add to a crisis in the Persian Gulf region, where the United States and Iran are trading low-level hostilities and where Iranian soldiers are boarding or seizing commercial ships.