Flooding in the aftermath of Hurricane Matthew has displaced several thousand people in North Carolina, and authorities were helping more evacuate on Tuesday as swollen rivers threatened a wide swath of the state. Governor Pat McCrory warned of "extremely dangerous" conditions in the coming days in central and eastern North Carolina, where several rivers were at record or near-record levels. Matthew, the most powerful Atlantic storm since 2007, killed at least 1,000 people in Haiti last week before barreling up the US southeastern coast and causing at least 30 deaths in Florida, Georgia and the Carolinas. McCrory's office said four additional deaths were confirmed on Tuesday in North Carolina, raising the death toll in the state to 18. One person was reported as missing. An additional US death occurred on Monday night in Lumberton, North Carolina, where officials said a highway patrol officer fatally shot a man who became hostile and flashed a handgun during search-and-rescue efforts in fast-running floodwater. Nearly 4,000 people have taken refuge in North Carolina shelters, including about 1,200 people in the hard-hit Lumberton area, where the Lumber River had crested at almost 4 feet (1.2 meters) above the prior record set in 2004 after Hurricane Frances. Water blanketed the city of 21,000 people, leaving businesses flooded, homes with water up to their roof lines and drivers stranded after a stretch of Interstate-95 became impassable. "We lost everything," said Sarah McCallum, 62, who was staying in a shelter set up in an agricultural center after floodwaters drove her from her home of 20 years. State officials are particularly concerned about victims like McCallum, who have no flood insurance because they do not live in areas typically prone to inundation. US President Barack Obama on Monday signed a disaster declaration for North Carolina, which will make federal funding available to people in the hardest-hit areas.