Survivors of the 2002 Bali blasts were incensed on Thursday after one of the bombmakers was released from an Indonesian prison halfway into his 20-year sentence, with one Australian terming the release "laughable".
Umar Patek was a member of an Al Qaeda-linked group that detonated two bombs outside a Bali bar and nightclub in October 2002, killing 202 people -- including 88 Australians.
Patek was released on parole Wednesday by Indonesian authorities, despite repeated pleas from the Australian government to keep him behind bars.
Australian attack survivor Peter Hughes, who spoke at Patek's trial in 2012, said the convicted extremist deserved to serve the "harshest sentence".
"For him to be let out, it's laughable," he told Australian national broadcaster ABC.
Indonesian authorities said they believed Patek had rehabilitated himself inside prison after completing a deradicalisation program.
Patek has said he wanted to devote himself to deradicalising other inmates.
Australia's deputy prime minister Richard Marles urged Indonesia to keep Patek under "constant surveillance".
"We will continue to make representations to make sure that there is constant surveillance of Umar Patek," he told ABC.
"I think this is going to be a very difficult day for many Australians."
Australian Prime Minister Anthony Albanese in August said he had nothing but "contempt" for Patek's actions and that his early release would be traumatic for victims' grieving families.
Hundreds of mourners and survivors gathered in Bali and Australia in October to mark the 20th anniversary of Southeast Asia's deadliest terror attack.
Back in Bali, speaking at a monument for victims built metres from the site of the blasts, Indonesian survivor Thiolina Marpaung said she felt "very sad" after hearing of Patek's parole and cast doubt on whether the Indonesian government would "properly" supervise him.
Patek is required to follow a training programme until 2030 as part of his parole.
His release came on the same day as a suicide bombing carried out by an Islamic militant who had already spent four years in jail for his involvement in a 2017 attack.
A police officer was killed and 10 people were wounded in the bombing targeting a police station in the Javan city of Bandung.
"The bomber in Bandung was just released in 2021 but less than a year later, he committed a suicide bombing. So, how about controlling Umar Patek until 2030?" Marpaung said.
Another survivor, I Dewa Ketut Rudita Widia Putra, said he was "very shocked" to learn about Patek's release, while also calling on the government to review early releases for terrorism convicts.
"I feel that it's odd that such a crime against humanity can be granted parole," Putra told AFP.