BREAKING! AT LEAST 20 KILLED IN MANCHESTER, ENGLAND AT ARIANA GRANDE CONCERT!

At least 20 people were killed and possibly “hundreds” of others were injured after one or more loud bangs were heard Monday night at an Ariana Grande concert at Manchester Arena in England, multiple law enforcement told NBC News.

Law enforcement sources in both Britain and the United States told NBC News there were possibly two explosions. There was no immediate information on what kind of explosions occurred, and the sources stressed that the information was preliminary and subject to change.

Greater Manchester Police said only that there were “a number of confirmed fatalities and injuries” as hundreds of fans fled the arena. Emergency crews rushed to the scene after the possible blasts, which were first reported about 10:40 p.m. (5:40 p.m. ET).

New York City counterterrorism police said they were monitoring developments.

“Ariana is okay,” a representative said. “We are further investigating what happened.”

Likewise, Bianca Landrieu, the Boston hiphop star known as Bia, who also performed, tweeted: “Guys we are okay!!!”

British Transport Police said officers were at the arena, which sits atop the Manchester Victoria transit station. All lines to Manchester Victoria were closed, National Rail said in a statement. Northern Railway said the station had been evacuated.