Friends and family have been mounting urgent appeals on social media under the hashtag #MissingInManchester after the suicide attack at an Ariana Grande concert at Manchester Arena.
Many people remain unaccounted for after attending the concert, where at least 22 died and 59 were injured.
Concerned relatives and friends have been urged to call an emergency police hotline on 0161 856 9400.
- Appeals have been issued for the following missing people
Charlotte Campbell, whose daughter Olivia, 15, has not been seen since the concert, issued a tearful plea for information.
Her daughter was at the venue with a friend who has since been found in hospital with injuries.
There is still no sign of Olivia, whose phone is not ringing.
She said: I’m heartbroken at the moment, because I don’t know where she is. I don’t know if she’s alive even yet.
"We are constantly ringing her phone but it is just going straight through saying that it cannot be connected at the moment."
Stuart Aspinall appealed for news on his friend Martyn Hett, who he was at the concert with.
He wrote on Facebook: "There was an explosion at the Ariana Grande concert tonight in Manchester and I haven't seen my friend Martyn since.
"He went to the bar about 20 minutes before the end of the concert and got chatting to some girls. As I was leaving, the explosion happened and everyone started running."
Martyn had posted on Facebook on Monday saying it was his last day in Manchester before going to America for two months.
Micheal Macintyre tweeted: "Looking for my daughter and her friend. Laura Macintyre and Eilidh Macleod."
However it has since emerged that Laura is in hospital being treated for serious injuries.
The whereabouts of her friend Eilidh are not yet known.
Debbie Mcdowell appealed for information about her best friend Wendy Fawell who is missing after the bombing.
Many Twitter users appealed for information on Chloe Rutherford and Liam Curry.
Student Alex Klis appealed on Facebook for help to find her parents.
Chantelle Garrity tweeted: "Please if anyone has seen my friend Kelly Brewster let me know. Her family friends need to know she is ok."
- Missing children found after desperate appeals
Some families shared their relief after loved ones were found safe and well after a long night of desperate phone calls.
One woman cried as she described how her niece was missing for several hours after becoming separated from her friends in the panic.
The girl, who was later found safe, was among several dozen lost children after the attack.
Many were taken in by two nearby hotels - Holiday Inn and Premier Inn - and taken care of while their family members were found.