Ariana Grande 'broken' after UK concert terror attack

US pop star Ariana Grande said  that she was "broken" and at a loss for words over the deadly terror attack at her concert in the British city of Manchester.

"Broken. From the bottom of my heart, I am so so sorry. I don't have words," she tweeted hours after a powerful blast ripped through a crowded arena hosting her concert, killing 19 people and injuring over 50 others.

Eyewitnesses said the explosion was heard outside the auditorium after the artist had finished her show and left the stage.

Grande, a 23-year-old American TV teen actress-turned-pop star, is a big draw for young fans, with hits including Problem, featuring Iggy Azalea, which hit number one in the UK in 2014, and Side To Side, featuring Nicki Minaj.

She is currently on a European tour and has already played in Birmingham and Dublin and was due to be at the O2 Arena in London tomorrow and Thursday.

However, following the blast there was no clarity on whether she will continue with her tour.

Her current 'The Dangerous Woman Tour' is in support of her third studio album, 'Dangerous Woman' which released last year on May 20. The tour began on February 3, in Phoenix, Arizona.

The album is the follow-up to her 2014 studio album 'My Everything' and features guest appearances from Minaj, Lil Wayne, Macy Gray and Future. The lead single "Dangerous Woman" was released on March 11, 2016.