When Indonesia's anti-drug chief, Budi Waseso, announced plans to guard a death-row prison island with crocodiles earlier this week, pointing out that they can't be bribed, the government rushed to explain the idea away as just a joke. But Waseso defied the suggestion of humor on Friday and doubled down on the idea, saying that he now wants to add tigers and piranha fish to add an additional layer of security.

The head of the National Narcotics Agency said that he had already gotten two crocodiles from a farm to study their power and aggression, according to Indonesia's Rima News, and noted that he might ultimately put as many as 1,000 in place around the prison to keep convicts from escaping.

"The number will depend on how big the area is, or whether perhaps to combine them with piranhas," Waseso told reporters, who were probably still trying to figure out if he was serious. "Because the (prison) personnel numbers are short, we can use wild animals. We could use tigers too — for conservation at the same time."

Waseso originally proposed his idea to replace prison guards with ferocious animals on Sunday, which he said would cut down on the corruption notorious in Indonesia's prison system.

"You can't bribe crocodiles," he said. "You can't convince them to let inmates escape."

In separate comments on the TVOne channel, Waseso rejected critics who said his plans to use animals as guards violated the human rights of convicts.

"We have to look at the whole problem," he said. "These people are murderers — mass murderers. Shouldn't we also look at the human rights of their victims?"

The Ministry of Justice and Human Rights is currently searching for a location in the country that would be suitable for the future prison.

Indonesian President Joko Widodo has declared a war on what he has called a "narcotics emergency," citing a study that showed at least 40 people a day were dying from drug use.

His government has taken a particularly harsh stance against drug dealers to combat high rates of narcotic use. Widodo has repeatedly refused clemency to traffickers and more than two dozen drug convicts, mostly foreigners, have been executed this year after a five-year moratorium on the death penalty. In April of this year, Indonesia executed two Australian drug traffickers by firing squad, prompting Australia to withdraw its ambassadors from the southeast Asian country.

The National Narcotics Agency had previously attracted controversy when an official suggested that traffickers caught with drugs should be punished by making them overdose on their own supply.