A 7.2 magnitude earthquake struck Haiti on Saturday, the United States Geological Survey said, prompting a tsunami alert and damaging buildings in the west of the disaster-plagued Caribbean nation.
The epicenter of the quake was about 160km by road from central Port-au-Prince, the densely populated capital.
The long shock was felt in neighboring countries.
The quake damaged schools as well as homes on Haiti's southwestern peninsula, according to images from witnesses.
Residents shared images on social media of the ruins of concrete buildings, including a church in which a ceremony was apparently underway on Saturday in the southwestern town of Les Anglais.
The USGS said waves of up to three meters were possible along the coastline of Haiti.
A magnitude-7.0 quake in January 2010 transformed much of Port-au-Prince and nearby cities into dusty ruins, killing more than 200 000 and injuring some 300 000 others.
More than a million and a half Haitians were made homeless, leaving island authorities and the international humanitarian community with a colossal challenge in a country lacking either a land registry or building codes.