Taylor Swift Devastated by UK Knife Attack at Dance Studio, 3 Girls Killed

Taylor Swift is grief-stricken after 3 children were killed and more severely injured in the UK at a dance class inspired by her music.

The mass stabbing in Southport was horrific, and clearly Taylor was feeling the grief by taking to her Instagram Stories Tuesday AM. She told her fans she's "completely in shock" that a knife-wielding 17-year-old could viciously attack a group of children and adults, who gathered to celebrate her discography.

She added ... "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."

After the attack, 2 of the children were confirmed dead by Merseyside Police Chief Constable Serena Kennedy, who also noted 9 others were injured. Per authorities, 6 were left fighting for their lives.

A 3rd child died Tuesday morning ... with 2 adults, who bravely tried to protect the children from the assailant, still in critical condition.

No motive yet for the attack, but police said it's not considered terrorist-related.

Swifties have rallied around the victims and their families, raising more than $135K for the victims and their families.

Taylor isn't the only notably name to come forward -- the royal family also sent condolences. King Charles issued a statement on behalf of himself and Queen Camilla -- saying they were "profoundly shocked" by the news.

Prince William and Kate Middleton released a similar statement, as they kept the victims in their thoughts and prayers after the "horrid and heinous attack."