At least 19 people have been killed during a stampede at the Love Parade dance music festival in the German city of Duisburg.
The German Police had been trying to stop overcrowding at the music event near a tunnel entrance but it is understood that people panicked and the deaths occured with over 100 people also left injured, according to the BBC.
Police and city officials have launched an investigation into what caused the disaster.
German Chancellor Angela Merkel has sent her condolences to the family and friends of the victims saying "Young people came to party. Instead, there was death and injury. I am aghast and saddened by the sorrow and the pain."
Duisburg Mayor Adolf Sauerland defended security measures for the festival and vowed to hold a full inquiry.
"In the run-up to the event, we worked out a solid security plan with the organisers and everyone involved," he said.
"The investigations that have already been launched must uncover the precise course of events."
More than one million people were believed to have attended the event when disaster struck at 17:00 local time.
Reuters news agency quoted police commissioner Juergen Kieskemper as saying the situation had become "very chaotic" with emergency services finding it difficult to get to victims aid.
A young woman told Die Welt: "Everywhere you looked, there were people with blue faces.
"My boyfriend pulled me out over the bodies, otherwise we would both have died in there. How can I ever forget those faces? The faces of the dead."
Police closed off an elevated motorway bridge to allow helicopters to land and evacuate victims.
City officials were said to have chosen not to evacuate the grounds of the day-long festival immediately, fearing it might spark more panic.
City spokesman Frank Kopatschek said: "The crisis meeting determined not to stop the event because at the moment there are too many people on the grounds."
Many of those attending appeared unaware of what had happened.
Organisers have since announced the festival will never happen again.
