Two people were killed and a dozen were injured on Saturday night when spectators rushed to the stage at an over-packed outdoor rock concert in eastern Argentina.

The deadly crush of fans was blamed on lack of crowd control at the concert of popular performer Indio Solari in the town of Olavarria, in Buenos Aires province.

Solari halted his performance several times, calling from the stage for security to help people who were stuck in the stampede and appeared to be fainting.

Some 350,000 fans showed up for the concert, Mayor Ezequiel Galli told a news conference. He said the event had been organized to handle less than half that number, and that it would be up to the justice system to decide who is to blame for the disaster.

"What happened was total chaos," he said. "It just got away from us."

"No one imagined that this many people would show up," he added, saying that by mid-afternoon some 100,000 vehicles, or one for every city resident, had arrived for the show.

A dozen people were hospitalized after being injured in the crush. Witnesses said the lack of control was such that organizers neglected to collect tickets at the large field where the concert was held, letting anyone through the gates.

The local bus system collapsed after the tragedy, stranding thousands of fans in Olavarria.