Joe Biden declared a federal emergency for swathes of Mississippi hit by a devastating tornado, as rescue workers continued to search for survivors on Sunday morning with a death toll of at least 26 people caused by catastrophic storms in parts of the US’s deep south. Twenty-five people were killed and dozens injured in Mississippi, throughout the state’s low-lying Delta region and around its north-east portion, with another man dying in the neighboring state of Alabama. The fatalities were the most for a tornado in Mississippi in more than five decades as the twister hit hardest in some of the most economically deprived areas of America’s poorest state. In the Delta town of Rolling Fork, with a population of about 2,000, entire neighborhoods were reduced to rubble. Video of the aftermath showed crushed cars, a toppled municipal water tower and bent trees shorn of their leaves. “The community has been destroyed,” said Rolling Fork’s mayor, Eldridge Walker, in an interview with ABC News on Sunday morning. “And now we’ve got to put the pieces back together again.” Walker, who is also a local funeral director and said he had lost friends during the catastrophe, added that he expected search and rescue to conclude Sunday with most community members now accounted for. “It’s devastating, and it’s heart shaking,” he said. “I extend my condolences to the families who have lost loved ones.” The town’s community hospital lost power during the storm, meaning patients and nursing home residents had to be transferred for treatment. The US congressman Bennie Thompson, who represents the Delta region in Washington and is the only Democrat in Mississippi’s congressional delegation, said on Saturday that many municipal buildings in Rolling Fork had been completely destroyed or badly damaged, including the police station, city hall and county courthouse. “There are a lot of things that are having to be put in place just for people to be able to get back,” Thompson told CNN. In nearby Carroll county, fatalities included three members of the same family living in a mobile home park near the community of Summerfield. Danny Munford, 51, his wife Helen Munford, 54, and their son JaDarrion Murphy, 14, died after winds picked up their mobile home and tore it apart, according to harrowing accounts reported by the Clarion-Ledger, the newspaper of the state capital of Jackson. Other family members who lived on the same land, including JaDarrion’s twin brother LaDarrion, survived and recalled searching for their loved ones in darkness. “We had to cut trees down before we were able to get to them, because trees were down everywhere,” Dede Duren, Helen Munford’s cousin, told the Clarion-Ledger. “Anything we saw, we saw with a flashlight or cellphone lights.” In the north-east Mississippi county of Munroe, the coroner confirmed to local media that a 34-year-old father and his one-year-old daughter were killed when the tornado hit their home in the small municipality of Wren. The man’s wife and two other young children survived but were badly injured, according to reports. Early National Weather Service estimates, derived from storm reports and radar data, highlighted the tornado’s vast scale and power. On a scale up to 5, the twister was given an EF-4 rating, meaning its top wind gusts were between 166 and 200mph. Weather service meteorologists estimated that the tornado was on the ground for more than one hour and traveled at least 170 miles, a distance that they described as “very, very rare”. The White House announced a major disaster early Sunday morning, unlocking federal funding to four counties in Mississippi hit hardest that can be used for temporary housing, repairs and other programs to help businesses and community members recover financially. The administrator of the Federal Emergency Management Agency (Fema), Deanne Criswell, was scheduled to visit Mississippi on Sunday. “We will do everything we can to help,” Biden said Saturday on Twitter. “We will work together to deliver the support you need to recover, for as long as it takes.” On Sunday, Mississippi’s Republican governor, Tate Reeves, thanked the Democratic president for “quickly approving our disaster declaration”. Reeves spent Saturday visiting communities around the state affected by the disaster, remarking: “The spirit of Mississippi is strong and we’re ready to rebuild!” Pope Francis included affected communities in Mississippi during Sunday prayers at the Vatican. The region continued to be pummeled throughout the weekend by torrid weather events. In Troup county, Georgia, at the state’s border with Alabama, a tornado on Sunday morning caused multiple injuries and damaged almost 100 structures. The National Weather Service in Mississippi warned of severe weather conditions throughout large portions of the state throughout Sunday, including large hail and the potential for more tornadoes. Severe weather warnings were also issued for parts of Louisiana and Alabama.