PORT-AU-PRINCE, Haiti (AP) — A powerful magnitude 7.2 earthquake struck southwestern Haiti on Saturday, killing at least 304 people and injuring at least 1,800 others as buildings tumbled into rubble. Prime Minister Ariel Henry said he was rushing aid to areas where towns were destroyed and hospitals overwhelmed with incoming patients.

The epicenter of the quake was about 125 kilometers (78 miles) west of the capital of Port-au-Prince, the U.S. Geological Survey said, and widespread damage was reported in the hemisphere’s poorest nations as a tropical storm also bore down.

Haiti’s ...