The US Geological Survey said a strong 6.5 magnitude earthquake struck off the north coast of Puerto Rico in the early hours of Monday.
It was felt in the capital San Juan, 60 miles from the epicenter, with reports of shaking buildings and minor damage but no injuries had been reported.
The Pacific Tsunami Warning Center earlier said the quake could cause a local tsunami, but this was later downgraded after monitoring by the Caribbean Tsunami Warning Program.
The US territory has a strong tourist sector, receiving 3.2 million visitors in 2013, mostly from North America, with a year on year increase of almost 5%.
The quake comes almost four years to the day since a devastating 7.0 magnitude earthquake hit nearby Haiti, causing the deaths of over 100,000.
