A stampede inside a tunnel crowded with techno music fans has crushed 19 people to death at Germany's famed Love Parade festival.

Thousands of other revelers kept partying at the event in Duisberg, near Dusseldorf, unaware of the deadly stampede that started when police reportedly tried to block thousands of people from entering.

The unconfirmed reports say the police closed off the area where the parade was being held because it was already over-crowded.

The party continued after the accident, with many of the other participants unaware of the stampede, news station n-tv reported. The Love Parade was once an institution in Berlin, but has been held in the industrial Ruhr region of western Germany since 2007.

The original Berlin Love Parade grew from a 1989 peace demonstration into a huge outdoor celebration of club culture that drew about 1.5 million people at its peak in 1999. But it suffered from financial problems and tensions with city officials in later years, and eventually moved.