At least 28 people are dead and tens of thousands without power after a storm system spawned a chain of tornadoes over three days across a large swath of the US, the Associated Press reported.
The storms flattened homes and businesses and forced frightened residents in more than half a dozen states to take cover.
More top news
The hashtag #RoomForManchester was being widely shared.
Witnesses reported hearing a "huge bang" at the venue during the concert on Monday evening.
ITV News travels to Britain's eastern-most city to gauge how the electorate will be casting its votes.