-Parents hunted for missing children after the blast. Many turned to social media to seek loved ones."Everyone pls share this, my little sister Emma was at the Ari concert tonight in #Manchester and she isn't answering her phone, pls help me," said one message posted alongside a picture of a blonde-haired girl with flowers in her hair.-Police said they were called at 10:33 pm after reports of an explosion. Manchester Chief Constable Ian Hopkins said police were treating the blast as a terrorist incident and were working with counter-terrorism police and intelligence agencies. They gave no further details on their investigation.-It is unclear where exactly the blast occurred, but initial reports indicated it happened either just outside the Manchester Arena or near a foyer.-It is also unclear whether it was a bomb. Police have so far not said what caused the blast.-US officials told Reuters that the timing and venue suggested a terror attack, possibly by a suicide bomber.-"This does not appear to have been a carefully planned attack involving multiple actors, extensive surveillance of the target or exotic materials," said another US official. "That is what is so worrisome about this kind of thing - how simple it is to indiscriminately kill, wound and terrorize innocent people. With our partners, the US has begun the process of combing through the available intelligence to see if anything was missed."-Prime Minister Theresa May said authorities were working to establish the full details of what police were treating as "an appalling terrorist attack." She said her thoughts were with the victims and the families of those who have been affected.-What about the June 8 election? PM May's ruling Conservative Party, which has a big lead in opinion polls, has suspended election campaigning due to the blast.-No militant group has claimed responsibility so far but Islamic State supporters celebrated on social media. Twitter accounts affiliated to the militant Islamist group have used hashtags referring to the blast to post celebratory messages, with some users encouraging similar attacks elsewhere.-The blast occurred on the anniversary of the murder of soldier Lee Rigby, who was hacked to death on a London street on May 22, 2013. Rigby's gruesome murder gained international notoriety when Michael Adebolajo was filmed by passers-by standing in the street with blood-soaked hands trying to justify the attack.broken. from the bottom of my heart, i am so so sorry. i don't have words.
— Ariana Grande (@ArianaGrande) May 23, 2017