Nineteen people have been killed and about 50 injured in a suspected terror attack at Ariana Grande's Manchester concert.

The cause of the blast is unknown but North West Counter Terrorism unit is treating it as a possible terrorist incident.

Greater Manchester Police at least 19 people are dead and about 50 people injured. They say there are a "number of confirmed fatalities and others injured." It's unclear if the injuries are from the stampede or from a blast.

Ariana Grande is inconsolable, "in hysterics" after learning at least 19 people were killed at her concert. Ariana is devastated that young people who came for a good time are now lying dead and injured.

Her next concert - Thursday in London at the O2 Arena -- is now up in the air for 2 reasons. It may constitute a safety threat, but also, as one source put it, "She's in no condition to perform." Ariana had just left the stage when a nail bomb exploded in the rotunda area near the front door as people were leaving the concert.  Ariana was not hurt.