Taylor Swift shared on Instagram that she is “completely in shock” after a stabbing attack at a Swift-themed dance class in Southport, England, left three children dead.

“The horror of yesterday’s attack in Southport is washing over me continuously, and I’m just completely in shock,” the singer-songwriter wrote on her Instagram story Tuesday. “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. I am at a complete loss for how to ever convey my sympathies to these families.”

A 17-year-old boy was arrested on suspicion of murder and attempted murder shortly after the bloody attack Monday during a Swift-themed dance and yoga class at a community center. Three children have died from the attack; eight children and two adults remain hospitalized.

A witness told The Associated Press that they saw several bloodied children running from the community center.

Police said there is no wider threat to the public and they aren’t treating it as a terror attack. Prime Minister Keir Starmer said the attack was “horrendous and deeply shocking.”