JOPLIN, Missouri -- The death toll from the May 22 Joplin, Missouri tornado rose to 138 Thursday, after hospitals confirmed four additional deaths from injuries, state officials said.

The death toll Wednesday stood at 134. State officials Wednesday said they had confirmed, either as located or deceased, every individual who was reported unaccounted-for in the wake of last week's tornado.

Missouri State Highway Patrol Troopers also completed their mission of notifying the next-of-kin of every deceased individual at the temporary morgue.

The massive F-5 tornado cut a six-mile swath through the southwest Missouri city. It was the deadliest single tornado in the United States since 1947.

Tornadoes have battered the country this spring, killing more than 500 people, mostly in the south. A twister struck Massachusetts Wednesday, where tornadoes are rare, killing four people.