A 5.5-magnitude earthquake has hit near southern Puerto Rico, jolting many people from their beds and causing damage across the island.
The US Geological Survey said the quake hit at a shallow depth of 2.5 miles (4km) near the city of Ponce and the towns of Guanica and Guayanilla on Saturday.
There have been no immediate reports of casualties.
These towns had already seen hundreds of homes destroyed, with one fatality and millions of dollars in damage by an earthquake in early January.
The latest quake struck as Puerto Ricans are ordered to remain home as part of a two-month lockdown to help curb coronavirus cases.
Reports of damage were still trickling on Saturday with at least one second-story balcony crashing in the southern city of Ponce, spokeswoman Ines Rivera said.
Meanwhile, cracks in homes were reported in Guayanilla.
"Everything shook really hard," spokesman Danny Hernandez said.
Meanwhile, in Guanica, Mayor Santos Seda said that no major damage has been reported so far, but he noted that between five to 10 people remain in a shelter since the 6.4-magnitude quake that hit in January.
"Thank God everyone is OK," he said. "The infrastructure is already weak."
Several aftershocks hit Puerto Rico's southern region, including a 4.6-magnitude one.
Victor Huerfano, director of Puerto Rico's Seismic Network, said that while it's understandable many people are afraid and surprised by the most recent earthquake, it's not unusual given the seismic activity that began in the region in late December.
"In the long run, it's decreasing, but you can have peaks," he said, adding that he expects strong aftershocks to continue.
Govenor Wanda Vazquez tweeted that rescue crews were fanning out across the area and that she would shortly be travelling there to meet with those affected in person.
"If your infrastructure is damaged, you must leave with your face mask on and your emergency backpack," she said as she urged people to remain calm.
But nerves are already frayed in many parts of the island as Puerto Rico continues to recover from Hurricane Maria, a string of strong earthquakes and the coronavirus.
Silvestre Alicea, a 67-year-old man who moved back to Puerto Rico from New York upon retiring, lost his home in January's earthquake and is still living with his sister in Guanica.
"This is unreal," he said, adding that some neighbours have left the area to stay with relatives elsewhere and that many, including a security guard who worked all night, are now sitting nervously in their balconies.
"He hasn't slept." Mr Alicea, however, said he decided to knock down a couple of breadfruits from a nearby tree as the aftershocks continue: "I'm taking it easy. There's nothing else you can do."
