Mexico City, Mexico — A plane crashed into a lake, killing 33 people and injuring 34 others Thursday, officials said.
Aircraft operator Southwest Airlines said it was investigating whether the crash occurred because of an electrical problem or mechanical failure.
No passengers or crew were aboard the Boeing 737-800 plane, the airline said in a statement.
The crash happened near the city of Acapulco, about 150 miles south of Mexico City.
The airline said the crash site is located in a river, where the water level is low.
The accident occurred after the plane took off from Acapolco, which is about 50 miles (80 kilometers) northwest of Mexico.
It was one of a series of accidents in the region that have prompted President Enrique Pena Nieto to call for tighter security measures, and prompted an international outcry.
The Associated Press contributed to this report.