It was centered 139 kilometers (86 miles) northwest of Montego Bay, Jamaica, and 140 kilometers (87 miles) west-southwest of Niquero, Cuba.
The quake hit at 2:10 p.m.
The weather service said there is a threat of tsunami waves reaching 0.3 to 1 meter (about 1 to 3 feet) above tide level for the coasts of Jamaica, Belize, Cuba, Honduras, Mexico and the Cayman Islands.
An earthquake of this scale is categorized as a major quake and can cause serious damage.
As of 2:36 p.m. ET, 157 people have reported that they felt the earthquake, according to the United States Geological Survey.
The quake could be felt strongly in Santiago, the largest far-eastern Cuban city.
The seismic activity had a depth of about 6.2 miles.
There were also several smaller quakes reported in and near Puerto Rico on Tuesday.
This developing story was originally published by Aliza Chasan at WPIX.