Sydney - Australia's foreign minister said on Thursday she had proposed a prisoner swap to her Indonesian counterpart in an 11th hour effort to save the lives of two Australian drug smugglers expected to face a firing squad within days.The planned executions of Myuran Sukumaran, aged 33, and Andrew Chan, aged 31, have ratcheted up diplomatic tension between Australia and Indonesia following repeated pleas for mercy on their behalf. They are among a group of up to 11 convicts, mostly foreigners, due to be executed on the prison island of Nusakambangan.Also facing execution are citizens of France, Brazil, the Philippines, Ghana and Nigeria, as well as Indonesia.Speaking after Australian politicians held a candlelight dawn vigil outside parliament house in support of the men, foreign minister Julie Bishop said she had spoken to Indonesia's foreign minister earlier this week."I raised the fact that there were Indonesian prisoners in Australian jails and whether there was an opportunity for us to consider a prisoner swap, a prisoner transfer or a clemency plea in exchange for a return of prisoners," Bishop told Sky News Australia."I just asked for a pause in their preparations for the execution of Mr Sukumaran and Mr Chan so that we could have officials explore these ideas."Australia does not have the death penalty and a recent survey by the Sydney-based Lowy Institute think tank showed nearly two-thirds of the public disapproved of the executions.Sukumaran and Chan were transferred from Bali's Kerobokan Prison on Wednesday to Nusakambangan, which lies off Java.Australian Prime Minister Tony Abbott said he had asked to speak again with Indonesian President Joko Widodo on Thursday.In an interview with Al Jazeera, Widodo said the men would be executed soon, but not this week."I am still convinced that the justice system in Indonesia, if you look at drug crime, is valid and based on facts and evidence," he said. "That's why when I rejected their clemency, I looked at their cases, how many drugs they were carrying."Indonesia is expected to decide on the date for the executions in a few days, said Tony Spontana, spokesperson for the attorney general's office.He declined to comment on Australia's prisoner swap offer.Tough stanceWidodo has adopted a tough stance against drug traffickers and others on death row, denying clemency appeals. Executions resumed in 2013 after a five-year gap and nationals from Brazil, Malawi, the Netherlands, Nigeria and Vietnam have been among those put in front of a firing squad.Chan and Sukumaran were convicted in 2005 as the ringleaders of the so-called Bali Nine, who were arrested at the holiday island's main airport for trying to smuggle 8kg of heroin to Australia.The seven other members of the gang, all Australians, have been jailed in Indonesia.The Australian government has stressed that Chan and Sukumaran have been rehabilitated in prison, where they have mentored younger inmates, and has warned of potential political repercussions if the executions go ahead.The pair have made numerous appeals against their sentences. One of those, which challenges Widodo's refusal of clemency, is still outstanding.