Concerned by swelling numbers of youth outside Riverfront Coliseum, Cincinnati police said they asked the promoter of Monday night's rock music concert here to open the doors of the mammoth auditorium, but he said he lacked the manpower to handle the crowd.

A half-hour later, 7,000 persons rushed the coliseum doors, leaving 11 dead and at least 22 injured, according to a preliminary report issued by Cincinnati police today.

Two of the victims were from Kentucky; the rest were Ohio residents. The youngest sophomores; the oldest was 22. One victim had two small children.

At a morning news conference, city officials indicated that strong measures would be taken immediately to minimize the potential for another such tragedy.

One of the measures, according to Cincinnati Mayor J. Kenneth Blackwell, could be the cancellation of concerts that pose a potential threat to patrons.

"If those measures mean shutting a concert down, you can bet that's what we'll do," Blackwell said.

The preliminary report to Cincinnati Police Chief Myron Leister from police officials at the scene indicated that by 6:30 p.m. Monday a large crowd had gathered at the concrete plaza in front of the coliseum overlooking a parking lot and the Ohio River 60 feet below.

Witnesses reported that some youths arrived as early as 3 p.m., drinking beer and smoking marijuana while they waited to grab the best spots for the performance by The Who.

Half the tickets for the concert were reserved. The other half were general admission, in which patrons sit on the main floor whereever there is room, an arrangement sometimes referred to as "festival seating."

According to city officials, police met with the promoter of the concert, Cal Levy of Electric Factory Concerts Inc., at 7 p.m. to request that the crowd be allowed to enter the building. The report said Levy told police that The Who had been late arriving and were still warming up, and that he did not have enough ticket-takers to handle the crowd.

Levy could not reached for comment today.

At 7:20 p.m., with 7,000 to 8,000 persons gathered outside, the first door was broken open. At 7:30 p.m., police said, they received several reports that persons had fallen and were being crushed, but the 35 officers assigned to the coliseum could not push through the crowd to aid the victims.

The first body was not reached until 7:45 p.m., police Lt. Dale Menkhaus said. Police later said that six of the victims died at the coliseum and five died en route to or at area hospitals.

Most of the 18,000 young persons whom the 35 policemen were to control at the concert were unaware at the concert's conclusion of the tragedy.

According to city Safety Director Richard Castellini, two banks of doors, with eight doors in each bank, were to opened on the west side of the concert hall to handle the crowd rush.

Castellini said 16 open doors was the standard number for most concerts.

Castellini said, "Festival seating has been a problem in the past and I think that after what has happened here, we are going to take a long hard look at it again, and I am sure there will be a move to see that it is never allowed to be implemented again.

The safety director said he plans to ask the city council to pass a law requiring that all seats be reserved at future events. "You don't have this kind of problem at a Reds or a Bengals game. It's the urgency of getting a seat that makes this happen," he said.

Blackwell summed up the incident this way: "A lot of young people apparently had been out a long time before the doors were opened. They were cold. Some were drinking alcohol, some were smoking marijuana, and when the doors were opened all sense of rationality left the group."

According to Blackwell, "The promoters seem to like festival seating, telling us that they save money on ushers and don't have to number reserved seats. They said it was difficult also to keep those who attend a rock concert in the area or the seat they have purchased. I think it is more profitable for them to have that type of seating."