JOPLIN, Mo. — The death toll from the monster tornado last week in Missouri has risen by seven to at least 139, city spokeswoman Lynn Onstot said Saturday.

The state has been working to pare down the list of people missing and unaccounted for in the wake of the deadliest single U.S. twister in more than six decades. It said Friday that the original list of 232 missing or unaccounted for residents had dropped to 156 by Friday, and planned to give an updated total later in the day.

Missouri Department of Public Safety Deputy Director Andrea Spillars said Friday that at least 90 people on the initial list had been located alive. But at least six others were identified as among the dead, and some new names had been added to the scroll of the missing. Authorities had cautioned for days that while they believed many on the list were alive and safe, others likely had been killed.

City Manager Mark Rohr acknowledged Friday afternoon that there may be “significant overlap” between the confirmed dead and the remainder of the missing list. Still, search and rescue crews were undeterred, with 600 volunteers and 50 dog teams out again across the city.

“We’re going to be in a search and rescue mode until we remove the last piece of debris,” Rohr said.

The tornado — an EF5 packing 200 mph winds — was the deadliest since 1950 and more than 900 people were injured. Tallying and identifying the dead and the missing has proven complex.

Earlier Saturday, a family member said that teenager Will Norton, believed to be ejected or sucked from his father’s car on the way home from graduation in the massive tornado, has been confirmed dead.