Australia will withdraw its ambassador from Indonesia in protest at the execution of two of its citizens for drug smuggling.
Prime Minister Tony Abbott said the executions of Myuran Sukumaran, 33, and Andrew Chan, 31, were "both cruel and unnecessary".
Brazil said the execution of one of its citizens "marks a serious event in the relations between the two countries".
In all eight people were executed, according to local media, including four Nigerians and an Indonesian man.
The Indonesian government refused to confirm the executions, but said a Philippine woman had been granted a reprieve.
Attorney General Muhammad Prasetyo said Mary Jane Fiesta Veloso had been granted a stay of execution while the Philippines investigates her case.
Gunshots were heard about 12.30am local time from Nusakambangan island where executions take place.
Mr Abbott told reporters: "These executions are both cruel and unnecessary.
"Cruel because both Andrew Chan and Myuran Sukumaran spent some decade in jail before being executed and unnecessary because both of these young Australians were fully rehabilitated while in prison."
Brazil had asked for a stay of execution for Rodrigo Gularte, 42, on humanitarian grounds because he was schizophrenic.
Brazilian Marco Archer Cardoso Moreira was one of six drug convicts including foreigners that Jakarta executed in January, brushing aside last-minute appeals from Brazil and the Netherlands.
Brazil and the Netherlands withdrew their ambassadors from Jakarta in protest at those executions.
Indonesian president Joko Widodo has vowed to show no mercy to drug criminals.
Veloso, 30, was arrested in 2010 at the airport in the central Indonesian city of Yogyakarta, where officials discovered about 5.5lbs of heroin hidden in her luggage.
Mr Prasetyo said she was granted a stay of execution because her alleged boss has been arrested in the Philippines, and the authorities there requested Indonesian assistance in pursuing the case.
"This delay did not cancel the execution. We just want to give a chance in relation with the legal process in the Philippines," Mr Prasetyo said.
Mary Jane Veloso's mother, Celia, told Manila radio station DZBB from Indonesia that what happened was "a miracle".
The news was welcomed by more than 250 Veloso supporters who held a candlelight vigil outside the Indonesian embassy in Manila.
"The call now here is to bring Mary Jane home and for her to be reunited with her family because she's a victim and she's innocent," protest leader Renato Reyes said.
The woman who allegedly recruited Veloso to work in Kuala Lumpur, Maria Kristina Sergio, surrendered to police in the Philippines on Monday, National Police Officer-in-Charge, Deputy Director-General Leonardo Espina said.
Veloso has maintained she was used as a drug mule without her knowledge.
Michael Chan, brother of Andrew Chan, who became a Christian pastor during his decade in prison and married an Indonesian woman on Monday, reacted with anger.
"I have just lost a courageous brother to a flawed Indonesian legal system. I miss you already RIP my Little Brother," Michael Chan tweeted.
"Today we lost Myu and Andrew, our sons, our brothers," the Sukumaran and Chan families later said.
"In the 10 years since they were arrested, they did all they could to make amends, helping many others. They asked for mercy, but there was none."
The executions were widely condemned.
"The execution of these eight people for non-violent drug offences will do nothing to reduce the availability of drugs in Indonesia or other countries, or protect people from drug abuse," said Ethan Nadelmann, executive director of the New York-based Drug Policy Alliance.
London-based Amnesty International called on Indonesia to abandon plans for further executions.
"These executions are utterly reprehensible," Rupert Abbott, Amnesty International's research director for South East Asia and the Pacific, said.
Originally, 10 inmates were to be executed, but Frenchman Serge Atlaoui was excluded from the latest executions because he still had an outstanding court appeal against Mr Widodo's rejection of his clemency application.
The government says Atlaoui will face a firing squad alone if his appeal is rejected by the Administrative Court.
The latest executions brought to 14 the number of drug traffickers shot in Indonesia under Mr Widodo's administration, which took power in October last year.
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