According to the U.S. Geological Survey, a 6.0 magnitude earthquake struck off the coast of Puerto Rico late Monday night.
There were no immediate reports of casualties or damage from the earthquake, which the agency said hit at a depth of 10 km and about 80 km from the northwestern coastal town of Isabela at 11:23 p.m. ET.
At least three aftershocks followed the initial earthquake, including a magnitude 4.7, the USGS said.
Emergency officials confirmed that there was no risk of tsunami.
TROPICAL STORM WARNINGS IN EFFECT
Monday night's earthquake came as the island remains under a tropical storm warning with Karen swirling just south of the region.
"On the forecast track, the center of Karen will pass near or over Puerto Rico and the Virgin Islands today, and then move over the western Atlantic tonight and Wednesday," said the U.S. National Hurricane Center in Tuesday's early morning update.
Tropical Storm Karen is expected to produce between 50-100 mm of rain over Puerto Rico and the Virgin Islands with the risk for isolated amounts up to 200 mm.
"These rains may cause flash flooding and mudslides, especially in mountainous areas," warns the NHC.