"This accident is so appalling that one can't put it into words," he added.
Officials, including the police, crisis management leaders and event organisers, have handed over documents to the prosecutors for a full investigation.
Survivors have blamed organisers for the deaths.
They said the site was too small and warnings of overcrowding had been ignored.
The Love Parade is a massive techno music event that was founded in Berlin in 1989. In recent years, it has grown so large that Berlin was no longer willing to host it for security and cost reasons.
The Love Parade planned for 2009, in neighbouring Bochum, was cancelled over security fears.
Its organiser Rainer Schaller said there would be no more Love Parade festivals.
"The Love Parade was always a peaceful and joyous party that will now forever be overshadowed by yesterday's tragic events," he said. "Out of respect for the victims, families and friends, we will discontinue the event. The Love Parade is no more."
Sauerland appealed to the public to let the investigation produce results before leveling accusations.
However, acting Duisburg Police Chief Detlef von Schmeling said that two separate criminal charges were already being considered by prosecutors, without giving further details.
Criticism of the organisation of the event has exploded in the wake of the deaths, focusing on the fact that at the time of the accident, only one entrance and exit point was available for the festival grounds, which cover a former goods railway yard.
"Young people came to party. Instead, there was death and injury"
Angela Merkel, the German chancellor
Both city officials and police defended the organisation and security planning of the event.
Union officials for the police force charged that organisers had put - financially motivated - pressure on the city to carry out the event despite budget and manpower constraints.
Wolfgang Orscheschek, spokesman for the German Police Union, said that pressure had been exerted "under the cover of the Capital of Culture 2010 banner" to hold the event.
The Ruhr valley region, of which Duisburg is a part, has been designated European Capital of Culture for 2010, with dozens of mass events so far having been carried out this year.
Police said that of the 19 dead - 11 women and eight men - all but one had been identified so far. Eleven were German citizens and two Spanish, with the others stemming from the Netherlands, Australia, Italy, China and Bosnia.
According to latest estimates, 342 people were injured, some of them seriously.
A British DJ told the BBC on Sunday of how organisers demanded that performers keep going even as the scale of the accident became clear, so that a second panic wouldn't break out.
"The organisers, they were quite adamant," DJ Mark Knight told the BBC. "We were told just before we were about to play 'the show has to go on. We cannot stop for fear of the repercussions and more panic.”
The party continued for at least five hours after the tragedy occurred.
Police said at the press conference that the deaths in the crush in fact occurred on the access ramps that connected the tunnel to the event grounds, and not within the tunnel itself as previously thought.
The panic occurred shortly after people tried to climb up fences and walls to escape the jammed tunnel area, with victims who had passed out from lack of oxygen being carried overhead.
German Chancellor Angela Merkel expressed her sorrow and shock at the fatal accident.
"In these difficult hours my thoughts are with the relatives of the victims. My sympathies and my sorrows go out to them," the chancellor said late on Saturday.
"The young people came to celebrate, instead there were deaths and injuries. I am appalled and distressed at the suffering and pain," she said.