A magnitude 7.2 earthquake struck Haiti early Saturday morning, the U.S. Geological Survey said.
The quake struck 12 km (7 miles) from the town of Saint-Louis du Sud, at a depth of 10 km, the USGS said.
The Associated Press reported that at least 227 people have died, and hundreds are missing or injured.
The U.S. Tsunami Warning System said there was a tsunami warning after the quake.
According to the AP, people in the capital of Port-au-Prince felt the tremor, and many of them rushed out into the streets in fear.
The AP reported that prime minister Ariel Henry said he was sending aid to towns damaged by the quake and hospitals overwhelmed with casualties.
Henry declared a one-month state of emergency for the whole country.
He added that he would not ask for international help until he knew the extent of the damages.