Survivors of a stampede at a free dance music festival in Germany in which 19 people were killed have blamed organisers for the deaths.

Witnesses criticised the decision to have just one entrance through a tunnel to the Love Parade, and said they had warned police about overcrowding.

The mayor of Duisburg, where the festival took place, said a security plan had been worked out beforehand.

Officials have launched an investigation into the disaster.

Most of the victims were trampled to death at an entrance tunnel connecting an old railway station to the parade ground. Police closed the exit to the tunnel and those trying to get in were told via loudhailer to turn around, but panic broke out.

Eyewitnesses claim they tried to warn police before the stampede occurred that the tunnel was overcrowded, but said the authorities ignored their warnings.

"You cannot jail one million people behind fences, you need to let them walk around free, then such things do not happen," one witness told journalists.

British DJ at the festival: ''Organisers told us to carry on playing."
One local resident told APTV: "Three days ago I thought the organiser was stupid because he only made one entrance point to the Love Parade. You can't lock so many people away behind a fence. That doesn't work."

About 300 people were also injured, dozens seriously. Officials said emergency workers had difficulties reaching the injured because of the massive crowds.

The founder of the Love Parade, who goes by the name of Dr Motte (Dr Moth), criticised the decision to have one entrace to the parade area.

"The organisers showed not the slightest responsibility for people. One single entrance through a tunnel lends itself to disaster. I am very sad," he said.

German Chancellor Angela Merkel has sent her condolences to the family and friends of the victims.

"Young people came to party. Instead, there was death and injury. I am aghast and saddened by the sorrow and the pain," she said.

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."

The exact circumstances of the stampede are still not clear.

Reuters news agency quoted police commissioner Juergen Kieskemper as saying the situation had become "very chaotic".

It appears most of the victims were crushed to death, however the authorities also suggested that some of those killed or injured might have attempted to flee the crowd by jumping over a barrier and falling several metres.

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."

The Love Parade attracts music fans from all over the world, with floats from Brazil, Russia, the Netherlands, Spain and Australia among other nations.

The floats had been expected to parade through the city for 10 hours. Many top international DJs also perform.

The event began in Berlin in 1989 as a peace demonstration and developed into a huge open-air music festival.