A major earthquake struck western Haiti on Saturday morning and was felt across the Caribbean. Fatalities have been reported.
People fled their homes for fear that buildings might collapse when the magnitude 7.2 tremor struck at approximately 8.30am.
A 5.2 magnitude aftershock was also recorded about 20 minutes after the initial shaking.
The epicentre of the quake was 8km (5 miles) from the town of Petit Trou de Nippes, about 150km west of the capital Port-au-Prince.
“High casualties are probable and the disaster is likely widespread,” the USGS says.
Initial images from the region show rubble in the streets and partially collapsed buildings. Many buildings are not built to withstand such shaking.
Haiti is still recovering from a magnitude 7 earthquake closer to the capital 11 years ago that killed hundreds of thousands of people and flattened swathes of buildings, leaving many homeless.
Further complicating any recovery, Tropical Storm Grace is due to pass over Haiti as soon as Tuesday.