PORT-DE-PAIX, Haiti — A magnitude 5.2 aftershock struck Haiti on Sunday, even as survivors of the previous day's temblor were sifting through the rubble of their cinderblock homes. The death toll stood at 12, with fears it could rise.

The U.S. Geological Survey said the epicenter of the aftershock was located 9.8 miles (15.8 kilometers) north-northwest of Port-de-Paix, the city hard hit by Saturday night's 5.9 magnitude earthquake. Sunday's aftershock had a depth of 10 kilometers.

"It was an aftershock. It was at the same location," said Paul Caruso, a geophysicist with the USGS. "This is the first significant aftershock."

The tremors caused panic on streets where emergency teams were providing relief to victims of Saturday's quake, which toppled cinderblock homes and rickety buildings in several cities.

Haiti's civil protection agency said at least eight people died in the coastal city of Port-de-Paix and three people died in the nearby community of Gros-Morne in Artibonite province. Another person died in Saint-Louis du Nord, Communication Minister Eddy Jackson Alexis tweeted.

Among the dead from Saturday night's quake were a 5-year-old boy crushed by his collapsing house and a man killed in a falling auditorium. Authorities said 188 people were injured.

"I feel like my life is not safe here," said nun Maryse Alsaint, director of the San Gabriel National School in Gros-Morne, where several classrooms were severely damaged.

She said that about 500 students would not be able to return to school on Monday.

Impoverished Haiti, where many live in tenuous circumstances, is vulnerable to earthquakes and hurricanes. A vastly larger magnitude 7.1 quake damaged much of the capital in 2010 and killed an estimated 300,000 people.

President Jovenel Moise urged people to donate blood and asked international aid agencies to coordinate with local agencies to avoid duplicated efforts. By Sunday evening the government didn't provide an estimate of the damages.

The USGS said Saturday's quake was centered 12 miles (19 kilometers) northwest of Port-de-Paix, which is about 136 miles (219 kilometers) from the capital of Port-au-Prince.

It was felt lightly in the capital, as well as in the neighboring Dominican Republic and in eastern Cuba, where no damage was reported.

In Haiti, officials have struggled to shore up buildings despite the two major fault lines along Hispaniola, which is the island shared with the Dominican Republic. Deep poverty and government instability have also rendered weaker homes and structures particularly vulnerable in earthquakes.

Rescue workers in Haiti said they were not looking for any more victims.

In the town of Gros-Morne, one bed was covered in rubble, while the exterior walls of some homes were visibly cracked. Others tilted at precarious angles.

Pierre Jacques Baudre, a farmer and father of seven, said he was afraid to return to his home after one wall built with rocks and cement crumbled.

"The house can fall at any time," he said.

Meanwhile, dozens of people could be seen sifting through debris before hauling away rebar to recycle and sell.

The civil protection agency issued a statement saying that houses were destroyed in Port-de-Paix, Gros-Morne, Chansolme and Turtle Island.

Damage was also reported at the Saint-Michel church in Plaisance and the police station in Port-de-Paix. Parts of a hospital and an auditorium collapsed in Gros-Morne, where parliamentarian Alcide Audne told The Associated Press that two of the deaths occurred.

Haiti President Jovenel Moise said on his Twitter account Sunday that civil protection brigades were working to clear debris. He also said the government had sent water and food.