Jakarta - Indonesia has asked foreign embassies to send representatives to a maximum security prison ahead of the expected execution of 10 drug convicts, although an official 72-hour notice of execution has not been given yet, diplomats said on Friday.Among the convicted drug offenders set to face the firing squad are nationals from Australia, Brazil, France and Nigeria and the case has strained relations between the governments of those nations and Indonesia.The Attorney General's Office said it expected to announce the date of execution in the next few weeks.Embassy officials received text messages from the government to send representatives on Saturday to the prison island of Nusakambangan, where the executions will soon take place. It was not clear why they were being summoned so early."The Attorney General's Office issued a blanket statement to embassies involved to send representatives. They did not say for what purpose," said an embassy official, who asked not to be named because he was not authorised to speak to the media."Our worst fear right now is that it's in preparation for possible executions."Security at the prison was heightened on Friday and religious counsellors, doctors and the firing squad were alerted to start final preparations.The Attorney General has been waiting for all the legal processes of the 10 death row inmates to be completed before announcing an execution date.Lawyers were scrambling to various Indonesian courts in a last-ditch attempt to delay the execution. But the only outstanding appeal considered still valid by the attorney general was for an Indonesian national, said spokesperson Tony Spontana.Philippine Vice President Jejomar Binay was expected to meet President Joko Widodo on Friday, during a visit to Indonesia to make a final appeal for mercy on behalf of one of its citizens among the group of 10.Bali NineFrance has warned Indonesia the executions could damage ties, while Australia has pleaded repeatedly for clemency for Andrew Chan and Myuran Sukumaran, two Australians arrested as ringleaders of the so-called Bali Nine drug-smuggling group."I fear that Indonesia will seek to proceed with the execution of the two Australian citizens," Australian Foreign Minister Julie Bishop told reporters after a visit to Nato headquarters in Brussels on Friday."I am asking of President Widodo what he asks of other countries in relation to Indonesian citizens who face death row overseas. Australia opposes the death penalty, whether at home or abroad, and we again appeal to President Widodo to show mercy."The members of the Bali Nine were arrested at the main airport on the holiday island of Bali for trying to smuggle 8kg of heroin to Australia. The seven other members of the gang, all Australians, have been jailed in Indonesia.Indonesia has harsh punishments for drug crimes and resumed executions in 2013 after a five-year gap. Six executions have been carried out so far this year.