The updated figures from Haiti's Office of Civil Protection follow a previous count of 304 dead. The office's director, Jerry Chandler, said rescuers are continuing to search for possible survivors under the rubble. 

People in the Caribbean island nation rushed into the streets to seek safety and to help help rescue those trapped in the rubble of collapsed homes, hotels and other structures. 

Saturday's earthquake struck the southwestern part of the hemisphere's poorest nation, almost razing some towns and triggering landslides that hampered rescue efforts in two of the hardest-hit communities. The disaster added to the plight of Haitians who were already grappling with the coronavirus pandemic, a presidential assassination and a wave of gang violence. 

The epicenter of the quake was about 125 kilometers (78 miles) west of the capital of Port-au-Prince, the U.S. Geological Survey said. The widespread damage could worsen by early next week, with Tropical Storm Grace predicted to reach Haiti late Monday or early Tuesday, bringing torrential rains. 

Aftershocks were felt throughout the day and through the night, when many people now homeless or frightened by the possibility of their fractured homes collapsing on them stayed in the streets to sleep — if their nerves allowed. In the badly damaged coastal town of Les Cayes, some families salvaged their few belongings and spent the night at an open-air football pitch. On Sunday morning, people lined up to buy what little was available: bananas, avocados and water at a local street market. 

Some in the town praised God for surviving the earthquake, and many went to the city's cathedral, which appeared outwardly undamaged even if the priests' residence was destroyed. 

"We only have Jesus now,'' said Johanne Dorcely, 58, whose house was destroyed. "If it wasn't for Jesus, I wouldn't be able to be here today.'' Prime Minister Ariel Henry said he was rushing aid to areas where towns were destroyed and hospitals overwhelmed with patients. A former senator rented a private airplane to move injured people from Les Cayes to Port-au-Prince for medical assistance. 

Henry declared a one-month state of emergency for the whole country and said he would not ask for international help until the extent of damage was known. 

"The most important thing is to recover as many survivors as possible under the rubble," said Henry. "We have learned that the local hospitals, in particular that of Les Cayes, are overwhelmed with wounded, fractured people." Rescue workers and bystanders were able to pull many people to safety from the rubble. Chandler said a partial survey of structural damage found at least 860 destroyed homes and more than 700 damaged. Hospitals, schools, offices and churches were also affected. 

On the tiny island of Ile-a-Vache, about 6.5 miles (10.5 kilometers) from Les Cayes, the quake damaged a seaside resort popular with Haitian officials, business leaders, diplomats and humanitarian workers. Fernand Sajous, owner of the Abaka Bay Resort, said by telephone that nine of the hotel's 30 rooms collapsed, but he said they were vacant at the time and no one was injured. "They disappeared — just like that," Sajous said. 

People in Les Cayes tried to pull guests from the rubble of a collapsed hotel, but as the sun set, they had only been able to recover the body of a 7-year-old girl whose home was behind the facility. "I have eight kids, and I was looking for the last one," Jean-Claude Daniel said through tears. "I will never see her again alive. The earthquake destroyed my life. It took a child away from me." The reports of overwhelmed hospitals come as Haiti struggles with the pandemic and a lack of resources to deal with it. The country of 11 million people received its first batch of U.S.-donated coronavirus vaccines only last month via a United Nations program for low-income countries. 

The earthquake also struck just over a month after President Jovenel Moïse was shot to death in his home, sending the country into political chaos. His widow, Martine Moïse, who was seriously wounded in the attack, posted a message on Twitter calling for unity among Haitians: "Let's put our shoulders together to bring solidarity." As he boarded a plane bound for Les Cayes, Henry said he wanted "structured solidarity" to ensure the response was coordinated to avoid the confusion that followed the devastating 2010 earthquake, when aid was slow to reach residents after as many as 300,000 Haitians were killed. 

U.S. President Joe Biden authorized an immediate response and named USAID Administrator Samantha Power to oversee the U.S effort to help Haiti. USAID will help to assess damage and assist in rebuilding, said Biden, who called the United States a "close and enduring friend to the people of Haiti." Power announced Sunday that USAID was sending a search and rescue team at the request of Haiti's government. The 65-person team will bring specialized tools and medical supplies to assist with the disaster response, Power said on Twitter. 

Argentina and Chile also were among the first nations to promise help. 

The North Carolina-based aid group Samaritan's Purse announced Sunday it would airlift 13 disaster response specialists and 31 tons of emergency supplies to Haiti. Those include shelter materials and water filtration units. 

Humanitarian workers said gang activity in the seaside district of Martissant, just west of the Haitian capital, also was complicating relief efforts. "Nobody can travel through the area," Ndiaga Seck, a UNICEF spokesman in Port-au-Prince, said by phone. "We can only fly over or take another route." Seck said information about deaths and damage was slow coming to Port-au-Prince because of spotty internet service, but UNICEF planned to send medical supplies to two hospitals in the south, in Les Cayes and Jeremie. 

People in Port-au-Prince felt the tremor and many rushed into the streets in fear, although there did not appear to be damage there. Haiti, where many live in tenuous circumstances, is vulnerable to earthquakes and hurricanes. A magnitude 5.9 earthquake in 2018 killed more than a dozen people. 

By early Sunday, the island had experienced six aftershocks stronger than magnitude 5.0 and more above 4.0. Claude Prepetit, a Haitian civil engineer and geologist, warned of the danger from cracked structures. "More or less intensive aftershocks are to be expected for a month," he said, cautioning that some buildings, "badly damaged during the earthquake, can collapse during aftershocks."