Andrew Chan, Myuran Sukumaran and other prisoners facing execution will be put through an “assimilation” process to mentally prepare them for the firing squad, Indonesia’s attorney general has revealed.

HM Prasetyo on Friday told reporters Jakarta was waiting for the legal avenues of some of the 10 drug felons awaiting execution to be exhausted before setting a date.

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He refused to call it a delay, even if he had earlier planned for the Bali Nine pair to spend as little time as possible on Nusakambangan, the execution island where they’ve been for more than a week.

“You interpret it as a waiting period, go ahead, but we’re respecting the ongoing legal process,” Mr Prasetyo said.

When the courts were finished, he said, the prisoners would be executed simultaneously.

He also flagged for the first time a period of “assimilation”.

“Assimilation is preparing mentally the death convicts who’s about to face execution,” he said. “There, they will be accompanied by religious figures until they’re truly ready.”

Chan and Sukumaran are in isolation cells where they can talk to each other but can’t mix with other prisoners besides one Nigerian, also on death row.

Prison authorities say there’s been no order to move them out, even though it’s clear they will be spending longer on the island than originally intended.

On Friday night, their supporters in Bali were devastated when an auction of Kerobokan prisoner’s paintings was ordered to be shut down by Jakarta.

The regular auctions fund supplies for the art classes and other projects launched with the imitative of the Australians.

This time however, prison authorities were unhappy with an unofficial flyer that promoted the auction as a tribute dedicated to Sukumaran.

The 90-plus paintings that were to be auctioned in Kuta were taken back to the prison, with a letter from the prison governor Sudjonggo saying the event was cancelled over concerns of “discrediting the process of … the implementation of the death penalty”.

The organisers say the event was never intended to be political, and they hope to reschedule the auction in order to keep the rehabilitation projects going.