The four were drug kingpin Freddy Budiman of Indonesia, Humprey Ejike and Michael Titus of Nigeria, as well as Seck Osmane, a Nigerian national but holding a Senegalese passport.
The convicts faced the firing squads at the Tunggal Panaluan shooting range in Nusakambangan Island off Central Javas southern coast at 12:46 a.m. local time on July 29.
Junior Attorney General for General Crimes Noor Rachmad did not offer any explanation on why only four out of the 10 were executed.
"(The decision was made) following a comprehensive study," he responded briefly.
Rachmad further remarked that the four had allegedly committed grave crimes, and the next wave of executions of the other death row inmates would be made public later on.
"Right now, we do not know whether the remaining death row inmates have appealed for clemency. Based on the result of our study with the existing team, only four would be executed for the time being. There are several aspects we have to take into account," he explained.
Attorney General H.M. Prasetyo had stated earlier that the 14 drug convicts on death row would face the firing squad.
The 14 death row inmates were Freddy Budiman, Merry Utami, Pujo Lestari, and Agus Hadi of Indonesia; Zulfiqar Ali of Pakistan; Gurdip Singh of India; Onkonkwo Nonso Kingsley, Obina Nwajagu, Michael Titus Igweh, Humprey Ejike Nih, Eugene Ape, and Gajetan Acena Seck Osmane of Nigeria; and Ozias Sibanda and Frederik Luttar of Zimbabwe.
The 10 inmates escaped the third wave of executions, as the prosecution attorneys had left Nusakambangan at 4:30 a.m. local time.
The bodies of the four inmates had also been moved from the notorious prison island on the same morning.
"The body of Freddy will be taken to Surabaya, the body of Ejike will be cremated in Banyumas, Central Java, while the bodies of Nigerians (Titus and Osmane) will be flown to their country of origin," Rachmad pointed out.
Budiman (37) was the first to face the firing squads in the wee hours of July 29.
Born in Surabaya, East Java, on July 19, 1979, Budiman had been given a death sentence by the West Jakarta District Court for importing 1,412,476 pills of ecstasy in May 2012.
Budiman had even continued to run a drug smuggling and trafficking racket from prison with the assistance of his men.
Following the execution of Budiman, Ejike was second on the list.
Ejike was arrested in Depok, West Java, in 2003 for possession of 1.7 kilograms (kg) of heroin.
Similar to Budiman, the Nigerian had also managed to run a drug trafficking business from prison.
Michael Titus (34) had been arrested for trafficking 5.8 kg of heroin, and Osmane (34) had been convicted on July 21, 2004, for possession of 2.4 kg of heroin in South Jakarta.
Indonesia is one of the few countries to have imposed the harshest drug laws in the world.
President Joko Widodo had emphasized that he would not grant clemency to drug convicts, who were responsible for the deaths of 50 Indonesians, mostly youngmen, every day, despite protests from several countries and parties at home.
Indonesia had executed 14 drug convicts on January 18, 2015, and April 29, 2015. Among the executed convicts were a 62-year-old Dutch citizen Ang Kim Soei, 48-year-old Malawian Namaona Denis, 53-year-old Brazilian national Marco Archer Cardoso Mareira, 38-year-old Nigerian Daniel Enemua, 38-year-old Indonesian citizen Andriani alias Melisa Aprilia, and 37-year-old Vietnamese national Tran Thi Bich Hanh.
Two members of the "Bali Nine" drug ring --- Andrew Chan and Myuran Sukumaran --- were also executed in April last year.
The first and second rounds of execution of the drug convicts were also carried out on the Nusakambangan Island.
In response to appeals by the UN and the EU to a implement moratorium on capital punishment, spokesman of the Indonesian foreign affairs ministry Arrmanatha Nasir on July 28 said that executions carried out by the Indonesian government of drug death row inmates was in accordance with, and not against, international laws.
"First, capital punishment is part of legal enforcement. Besides, I emphasize that that capital punishment is not against international laws," he said.
Nasir added that Indonesia is forced to impose capital punishment on drug traffickers and manufacturers, because the country has become a target for international drug trafficking.
Some 4.1 million Indonesians, particularly youths, are drug addicts, and some 40 to 50 people die every day due to drug abuse, he noted.
Further, drug abuse has resulted in state losses of Rp63 trillion annually, he said.
The death penalty has been seen as a positive law in Indonesia, and is not against the principles set forth in the 1945 Constitution, he explained.
Further, capital punishment is the final resort used to stop extraordinary crimes, including drug offenses, he noted.
Besides, drug criminals have gone through the legal process, while drug victims have gone into rehabilitation programs, he added.
The foreign ministry had informed concerned foreign embassies about foreign death row inmates to be executed.