Indonesia on Friday has asked foreign embassies to send representatives to a maximum security prison on the prison island of Nusakambangan for the expected execution of 10 drug convicts.
Two Australian citizens, Andrew Chan and Myuran Sukumaran, are among those slated to die.
Also set to face the firing squad are nationals from, Brazil, France, Nigeria, and the Philippines. The case has strained relations between the governments of those nations and Indonesia.
"It's true, we have been told to be there on Saturday," said a foreign embassy official who asked not to be identified because she was not authorized to speak to the media.
"We still don't know when the actual date of execution will happen but we expect that it will be in days."
A police spokesman said orders to prepare the firing squad had not yet come from the Attorney General's Office.
Final appeals rejected
This week, Indonesia's Supreme Court rejected the final appeals of a French prisoner and another from Ghana, according to media reports.
France has warned Indonesia that the executions could damage ties, while Australia has pleaded repeatedly for clemency for two Australians arrested as ringleaders of the so-called Bali Nine drug-smuggling group.
A lawyer for the two Australians said a letter of instruction had been sent from the office of the Indonesian attorney general to those responsible for carrying out the executions. He said it would be "a travesty" if they were executed while legal avenues were still being pursued.
Diplomats said, however, that an official 72 hour notice of execution has not been given yet.
av/bk (DPA, Reuters)