A third child has died after a knife attack in Southport, England, and five children and two adults remain in a critical condition, the police said on Tuesday.

A 9-year-old girl died in the hospital in the early hours of Tuesday, the police said in a statement, while two other girls, age 6 and 7, died on Monday as a result of their injuries.

The attack, which the local police chief, Serena Kennedy, described as “ferocious,” took place at a Taylor Swift-themed dance class for children age 6 to 11. A 17-year-old boy was arrested and is being questioned by the police.

Ms. Swift said in a statement about the attack on Instagram that she was “completely in shock.”

“The horror of yesterday’s attack in Southport is washing over me continuously,” she wrote, adding: “The loss of life and innocence, and the horrendous trauma inflicted on everyone who was there, the families, and first responders. These were just little kids at a dance class.”

Prime Minister Keir Starmer is expected to visit the scene on Tuesday, Rachel Reeves, the chancellor of the Exchequer, told Sky News.

Here’s what we know.

A group of children were attending a Taylor Swift-themed yoga and dance workshop at a studio in Southport on Monday when the attack took place.