'Broken... I am so, so sorry' - pop star Ariana Grande
US star Ariana Grande has said she is "broken" following a suspected terrorist attack at her Manchester Arena concert left 22 dead.
Dozens of others were injured in the explosion moments after the singer left the stage on Monday evening.
broken.— Ariana Grande (@ArianaGrande) May 23, 2017
from the bottom of my heart, i am so so sorry. i don't have words.
Tweeting in the early hours of Tuesday, the 23-year-old said: "broken. from the bottom of my heart, i am so so sorry. i don't have words."
Meanwhile Grande's management team, Scooter Braun Projects, said they had been left heartbroken by the incident and praised the actions of Manchester's emergency services.
They said in a statement: "Words cannot express our sorrow for the victims and families harmed in this senseless attack.
"We mourn the lives of children and loved ones taken by this cowardly act.
"We are thankful for the selfless service tonight of Manchester's first responders who rushed toward danger to help save lives.
"We ask all of you to hold the victims, their families, and all those affected in your hearts and prayers."
Meanwhile, musicians, actors and other entertainers used social media to offer their sympathies to those affected.
James Corden has paid an emotional tribute to Manchester as the news broke on Monday night.
Corden, presenting The Late Late Show, said: "It shocks me every time we hear this sort of news that attacks like this can happen, but especially when there will be so many children at this concert tonight.
"And I'm telling you, a more tight-knit group of people you will be hard pressed to find. Strong, proud, caring people with community at its core.
"And if it was even possible, the spirit of the people of Manchester will grow even stronger this evening.
"My thoughts and prayers are with the everyone in Manchester tonight."
He said viewers in the US would have heard of the city for "many wonderful things", including its two leading football teams and bands such as Oasis and Joy Division.
"It was the birthplace of the leader of the suffragettes. It's the home of the inventor of the first computer. It's a place full of comedy and curries and character," he added.
Many stars chose to pay their respects on social media.
Harry Styles said: "I'm heartbroken over what happened in Manchester tonight. Sending love to everyone involved."
Katy Perry tweeted: "Praying for everyone at @ArianaGrande's show."
Comedian Matt Lucas said his thoughts were with everyone affected by the "terrible attack".
Cher wrote: "My prayers go out to ppl of Manchester ... had special times there from youth and beyond."
KT Tunstall said she had just finished performing in London when she heard the "gut-wrenching" news, and added: "So very sorry for the families who have lost loved ones."
Nicki Minaj wrote: "My heart hurts for my sister, Ariana & every family affected by this tragic event in the U.K. Innocent lives lost. I'm so sorry to hear this."
Vernon Kay said: "Our thoughts are with all those families affected in Manchester ... Couldn't possibly imagine what's going on in the city I love."
Actor and former wrestler Dwayne "The Rock" Johnson offered his prayers to those affected.
Demi Lovato wrote: "Tearing up imagining innocent concert goers losing their lives. Praying for everyone and all."
The band Nickelback said: "Manchester you are in our hearts, thoughts and prayers. Sending all love and light to those affected. Stay strong."
Singer Halsey tweeted: "Hearing mixed things but hoping deeply the blast was an accident and not intentional. Music is a safe place."