German Chancellor Angela Merkel, President Christian Wulff and members of the cabinet Saturday took part in a memorial church service for the 21 victims of last week's fatal crush at the Love Parade dance music festival.

Wreaths from Merkel, Wulff and the other dignitaries were laid Saturday morning beside the sea of votive candles at the entrance to the access tunnel at the event grounds where the crush occurred.

The chancellor, who has interrupted her summer holiday to attend the service, spoke with relatives of the dead before the service.

At the Duisburg football stadium, space for up to 25,000 mourners had been made available to watch a live broadcast of the memorial service, which is taking place at the Salvatorkirche in the city.

By 11 a.m. (0900 GMT) as the service began, however, only a few hundred people were in the stadium.

The access tunnel to the festival grounds where the crush occurred July 24 as party-goers attempted to gain entry to the massive event has been sealed off.

Merkel joined some 500 mourners inside the church for the ecumenical service, along with relatives of the dead and injured. More than 500 people were hurt in the crush.

Some 25 remain in hospital, some with severe injuries.

Duisburg mayor Adolf Sauerland was not expected to attend the ceremony, as in recent days calls for his resignation have grown.

Angry protests have taken place outside the city hall, as blame for the tragedy has been traded between organisers, police and city officials.