JOPLIN, Mo. — A massive tornado that tore a 6-mile path across southwestern Missouri killed at least 89 people as it slammed into the city of Joplin, ripping into a hospital and leaving a forest of splintered tree trunks behind where entire neighborhoods once stood.

Authorities warned that the death toll could climb Monday as search and rescuers continued their work at sunrise.

City manager Mark Rohr announced the number of known dead at a pre-dawn news conference outside the wreckage of a hospital that took a direct hit from Sunday’s storm. Rohr said the twister cut a path nearly 6 miles long and more than a half-mile wide through the center of town, adding that tornado sirens gave residents about a 20-minute warning before the tornado touched down on the city’s west side.

Much of the city’s south side was leveled, with churches, schools, businesses and homes reduced to ruins.

Fire chief Mitch Randles estimated that 25 to 30 percent of the city was damaged, and said his own home was among the buildings destroyed as the twister swept through this city of about 50,000 people some 160 miles south of Kansas City.

“It cut the city in half,” Randles said.

An unknown number of people were injured in the storm, and officials said patients were scattered to any nearby hospitals that could take them.

Authorities planned to conduct a door-to-door search of the damaged area Monday morning, but were expected to move gingerly around downed power lines, jagged debris and a series of gas leaks that caused fires around the city overnight.

“We will recover and come back stronger than we are today,” Rohr said defiantly of his city’s future.