At least 19 people were confirmed dead Sunday after partygoers at a German music festival stampeded through a tunnel that served as the venue's sole entrance.

The Love Parade, a techno music party, will never be held again, founder Rainer Schaller confirmed at a heated press conference following the tragedy.

German Chancellor Angela Merkel promised a "very intensive investigation" into the deaths as prosecutors launched an official probe.

"This was a very, very dreadful and sad day," Merkel said. "We must do everything we can to ensure that something like this never happens again."

Amid reports of overcrowding and poor planning, organizers have provided scant information about why hundreds of thousands of people were funneled through a highway underpass and into the former railway station where the party was being hosted.

German media reported that officers in Duisburg, a city near Duesseldorf in Germany, closed one end of the tunnel when the venue became overcrowded. The entrance, however, remained open allowing people to pile in as others tried to leave.

"Fourteen people died on the metal steps leading away from the tunnel, two on a wall outside," said Deputy police chief Detlef von Schmeling Sunday.

Witnesses recalled a scene of panic with people piling on one another as others scrambled over those who had fallen.

"The organisation was very bad," said Patrick Guenter, a 22-year-old reveller.

"There was nothing to drink apart from alcohol and although the festival was full, they kept letting people in," he added.

More than 340 people are believed to have been injured.

"I saw 25 people piled on top of one another -- a huge heap," wrote one man online. "The people couldn't get any air. One person was completely pale and I wanted to give him some water, but a medic that wouldn't help him – he was already gone."

Those killed ranged in age between 20 and 40 and include an Australian, an Italian, a Chinese citizen and a person from Holland.

"It seems the organisers didn't plan the route. The road was very narrow," said Taggart Bowen-Gaddy, 20, a U.S. citizen from Philadelphia.

"There was no planning, no one knew what was going on."

Rescuers struggled to reach victims as many others at the venue remained unaware of any problem and the music continued. Officials opted to keep the concert going to avoid another crush of people trying to leave.

The cell phone system in the area temporarily froze, preventing anyone outside the venue from being able to reach partygoers. Frantic parents drove to the site to look for their children.

Orgainzers said that 4,000 police officers and 1,000 security personnel were brought in for the event. Media said that 1.4 million came for the party, but police have not confirmed that number.

The Stadt-Anzeiger paper nearby Cologne reported in its Monday edition that warnings about the party site were ignored last October.

The paper reported that Duisburg's mayor had been told that the city was too small to deal with the large influx of partygoers.

Duisburg Mayor Adolf Sauerland said that a thorough investigation would occur, but he said that a "solid security plan" had been put in place.

It was the worst accident of its kind since nine people were crushed to death and 43 more were injured at a rock festival in Roskilde, Denmark, in 2000. That fatal accident occurred when a huge crowd pushed forward during a Pearl Jam gig.

The Love Parade, where people from across Europe gather to dance, watch floats and listen to DJs spin, 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.

The website of the Love Parade -- whose motto this year was "The Art of Love" -- went black on Saturday night, with words in white saying:

"Our wish to arrange a happy togetherness was overshadowed by the tragic accidents today. ... Our sincere condolences to all the relatives and our thoughts are with all of those who are currently being taken care of."