So far, 22 people have been confirmed dead with at least 119 more victims injured.
Eight-year-old Saffie Roussos and 18-year-old Georgina Callander, a fan who met Grande two years ago and tweeted her excitement before the show, were among the 22 who died.
One concert goer told The Daily Mail that she witnessed a young girl screaming, "I don't know where my sister is!"
A man at the concert revealed that he held a dying woman in his arms as he saw a girl lose her legs in the blast.
Meanwhile, according to reports, a 23-year-old man was arrested in south Manchester on Tuesday, though authorities haven't publicly linked him to the attack. Hours later, another unnamed man was arrested in connection to the attack.
Shortly before the explosion, an unverified Twitter account posted cryptic messages featuring the ISIS flag alongside the hashtags #IslamicState and #Manchesterarena.
"You forget our threat? This is the just terror," the tweet read. The account was deleted soon after.
Police declined to comment on the tweets, though ISIS has since claimed responsibility, alleging "one of the caliphate's soldiers placed bombs among the crowds."
Hours after the tragedy, Grande announced that she'll be suspending the remainder of her world tour, writing on Twitter: "From the bottom of my heart, I am so so sorry. I don't have words."
"We mourn for the children," her manager, Scooter Braun, said.
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