A deadly explosion hit a well-known hotel in downtown Havana yesterday, tearing a gash several floors high in the side of the building, killing at least 22 people and injuring upwards of 70, witnesses and state media said.

Speaking from the scene on Cuban television, President Miguel Diaz-Canel said the blast at the historic, high-end Hotel Saratoga appeared to have been caused by a gas leak.

"In no case was it a...