Kamikawa said courts hand down death sentences for extremely heinous crimes after full deliberation.
Asahara had been on death row for masterminding a deadly 1995 Tokyo subway gas attack and other crimes. Asahara was executed at a Tokyo detention center, while the others were hanged at the same detention center as well as those in Osaka, Hiroshima and Fukuoka.
Some experts urged the ministry not to execute them as their experience could help prevent similar crimes. Some of those transferred were not among the seven hanged Friday. Japan usually does not execute people who are seeking retrial. "However, the death penalty is never the answer", said Hiroka Shoji, East Asia researcher at Amnesty International.
The former leader of a doomsday cult that carried out a deadly nerve gas attack on the Tokyo subway in 1995 was executed on Friday, Japanese media reported. Thereby, the New Era, to be named next year, will not be blighted by the most terrifying terrorist attack that hit Japan during the Heisei Era.
After Sakomoto's murder and the cult's growing notoriety amid cult members' families' protests, Aum Shinrikyo reportedly began preparing for the end.
The relatives of those killed in the attack, and others who were injured welcomed the executions.
Twelve other members of Aum Shinrikyo were sentenced to death for their roles in the Tokyo attack.
"A third of my life has been affected by AUM".
"When I heard the news, I reacted calmly".
Chief Cabinet Secretary Yoshihide Suga said the authorities were monitoring the activities of the cult's successor organisation, Aleph, after the executions.
Asahara's execution comes after 20 years of trials, with the Japanese government dismissing the final appeal earlier this year. Thirteen people were killed and more than 6000 sickened.
Asahara, who was 63 years old at the time of his execution, has been on death row since 2004.
Fortunately, mistakes made in developing the sarin and its delivery method meant the attack was far less effective than intended, and the group only succeeded in killing 12 and injuring 5,500 people. Despite this, over 2,000 members of another offshoot cult still follow the teachings of Shoko Asahara. The death sentence against him was finalized in 2006.
Asahara was captured two months later, dragged out of a hidden compartment in a ceiling where he had holed up to evade arrest.
AUM evolved from a yoga school established by Asahara in 1984 and had about 1,400 live-in followers and over 10,000 lay followers at one point.
Matsumoto said her family members had long demanded he be treated, Matsumoto said, but the Tokyo detention center and courts refused, saying he was in good health.
Between 2012 and 2016, 24 people were executed, according to the most recent justice ministry data.
The cult claimed to have 10,000 members in Japan and 30,000 in Russian Federation but has disbanded.
Shizue Takahashi, whose husband was a subway deputy station master who died in the attack, also expressed regret that six of Asahara's followers had been killed.
Aum Shinrikyo is believed to still have thousands of followers.