'I am so so sorry': 'Broken' Ariana Grande posts emotional tweet and suspends her world tour after 22 are killed in terrorist attack at UK concert

Speechless: The devastated singer posted a short and emotional message on her Twitter account

Ariana Grande said she's 'broken' and 'so so sorry' after 22 people died and 59 were injured in a terrorist attack at her Monday evening concert at the Manchester Arena in Manchester, England.

The singer, 23, wrote in an emotional tweet: 'broken. from the bottom of my heart, [I] am so so sorry. [I] don't have words.'

Ariana's manager, Scooter Braun, said: 'Tonight, our hearts are broken. 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.

He went on to thank authorities in Manchester for their rapid response to the disastrous occurrence, added: 'We ask all of you to hold the victims, their families, and all those affected in your hearts and prayers.'

Calm before the storm: Ariana Grande, 23, was photographed at her concert at the Manchester Arena Monday in Manchester, England

Tragic incident: The explosion occurred at about 10:35 p.m. local time, after Grande walked off the stage

Ariana has since suspended the entire European leg of her The Dangerous Woman Tour, with TMZ reporting the singer is 'incapable' of performing her next planned date in London on Thursday night.

Organisers are said to be 'deeply concerned about security' in the wake of the attack.

The singer was due to perform in England, Belgium, Poland, Germany and Switzerland over the coming weeks.

A father has told of the chilling last words Ariana told the crowd at Manchester Arena before the explosion went off.

He told the BBC: 'Ariana said: "Bye bye Manchester!" The lights came on then there was two big noises and people started running and shouting.

'When the doors opened I saw blood on the floor and two injured people. Blood all over their faces. A lot of people were in shock.'

Concertgoers who witnessed the carnage said that at about 10:35pm, a pair of loud explosions were heard in the building.

Majid Khan, 22, said that 'a huge bomb-like bang went off that hugely panicked everyone, and we were all trying to flee the arena.'

Father-of-two Shaun Hunter, who brought his daughters, ages 12 and 10 to the show, said there was a 'a stampede' of attendees toward the exits after the explosion. He noted, 'I saw one bloke carrying his daughter - she was bleeding.'