Rio 2016 organisers issued an apology on Tuesday after a jaguar that featured in an Olympic torch ceremony was shot dead in the Amazonian city of Manaus.
The jaguar, which had earlier been tranquilised, was killed by a single gun shot from a soldier after it escaped from handlers, the Brazilian army said in a statement.
The army said the soldier had been forced to shoot the animal to protect himself from being mauled, Xinhua reported.
"We made a mistake in permitting the Olympic torch, a symbol of peace and unity, to be exhibited alongside a chained wild animal," Rio 2016 said in a statement.
"This image goes against our beliefs and our values. We guarantee that there will be no more such incidents at Rio 2016."
The jaguar, named Juma, was the real-life version of Brazil's Olympic team toy mascot, known as Ginga.
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Animal rights groups questioned why Juma was used in the ceremony. Moments before being fatally wounded, the animal featured in photographs alongside the Olympic torch while shackled by chains.
"When will people (and institutions) stop with this sick need to show power and control by confining, taming and showcasing wild animals?" Brazilian animal rights group Animal Freedom Union said on Facebook.
According to the International Union for Conservation of Nature, the jaguar is an endangered species in the Americas. It's population has fallen by 30% since the mid-1980s.
Ipaam, Brazil's Amazonas state environmental authority, said it had launched an investigation in the incident.
"No request was made to authorise the participation of the jaguar 'Juma' in the event of the Olympic torch," Ipaam said in a statement.