An explosion at an Ariana Grande’s recent concert which has killed at least 19 people and injured around 50, is believed to have been the work of terrorists, police said.

The incident which took place at the Manchester Arena in England on Monday, 10.30pm, happened shortly after Grande had left the stage, CNN reports.

“This is currently being treated as a terrorist incident until police know otherwise,” Manchester police said on Twitter.

“We can confirm there was an incident as people were leaving the Ariana Grande show last night. The incident took place outside the venue in a public space. Our thoughts and prayers go out to the victims,” the post continued.

Traumatised concertgoers which were made up of mostly adolescents, screamed and fled in what appeared to be the deadliest episode of terrorism in Britain since the 2005 London subway bombings.

According to New York Times, Grande’s publicist, Joseph Carozza said that “Ariana is okay” and added, “We are further investigating what happened.”

Meanwhile, TMZ has reported that Ariana is “in hysterics” after learning that 19 people were killed at her concert.

She tweeted, “Broken. From the bottom of my heart, I am so so sorry. I don’t have words.”

Sources also said that her next concert in London’s O2 Arena this Thursday, is now up in the air as it may constitute a safety threat, but also, “She’s in no condition to perform.”