Ariana Grande 'Broken' After Manchester Arena Attack

U.S. pop star Ariana Grande late Monday said she felt at a loss for words after a suspected terror attack at her concert in the British city of Manchester.

"Broken," she wrote in her first reaction on Twitter.

"From the bottom of my heart, I am so so sorry. I don't have words," she wrote.

Police said at least 19 people were killed and around 50 wounded in the attack at the 21,000-capacity Manchester Arena.

Ariana Grande arrives at the 2016 American Music Awards at Microsoft Theater on November 20, 2016 in Los Angeles, California. (Photo by C Flanigan/Getty Images)

It was the deadliest attack in Britain since 2005.

Grande, a 23-year-old former child star, is not known for her political views and draws an audience of teenagers and pre-teenagers.

More coverage of the Manchester terrorist attack

• More Arrests Made In Connection With Manchester Suicide Bombing

• Grandmother Sheltered Dozens Of Teens In Hotel After Concert Attack

• Canadian Musicians Express Grief After Attack

• U.K. Citizens Start #RoomForManchester To Help Victims Of Attack

• How To Safely Get Out Of A Crowd In An Emergency