Police in the Peruvian capital, Lima, are investigating a grenade explosion during a circus performance which wounded 11 people, mostly members of the public.
Most of the injured had shrapnel wounds or damaged hearing and one circus worker, a clown, was taken to hospital with a stomach wound.
Police say they are investigating if extortionists were behind the attack.
Officials said they would be increasing security at six circuses in the area.
Police officers said they would be placing police both inside and outside the circuses to ensure public safety.
Correspondents in Lima say extortion has been on the rise in Peru, with new buildings, private schools and taxi drivers frequent targets.
Peru's chief prosecutor reported 1,667 complaints of extortion in the first four months of this year.
In June the Congress approved a request from the government for special legislative powers to reduce crime and improve security.
Interior Minister Jose Luis Perez Guadalupe said the government wanted to tackle an increase in contract killing and extortion that were becoming a major concern in certain areas of both Lima and other regions such as Ancash and the northern coast.
Crime is expected to be one of the main campaign issues in next year's presidential election.