Two men have been executed in Japan’s secretive death chambers, as human rights groups called for an end to the “deplorable” punishment.

Koichi Shoji, 64, and Yasunori Suzuki, 50, were hanged at two separate detention centres in Tokyo and Fukuoka in the early hours of Friday morning after being convicted of murder.

The executions were the first in the country this year but bring the total carried out under prime minister Shinzo Abe’s administration to 38. Another 110 people remain on death row.

“These executions demonstrate the Japanese government’s shocking disregard for human life,” said Roseann Rife, East Asia Research Director at Amnesty International, which opposes the death penalty in all cases.

“While the rest of the world increasingly turns its back on the death penalty, Japan remains stuck in the past by continuing with this ultimate cruel and irreversible punishment.

“It is deplorable that the government continues to carry out executions. As Japan prepares to host the UN Crime Congress next April, it is high time that its criminal justice system is reviewed to fully comply with international human rights law and standards.

“We urge the Japanese authorities to establish an immediate moratorium on all executions and promote an informed debate on the death penalty as first steps towards its abolition.”

Inside Japan's secretive execution chamber Show all 7 1 /7 Inside Japan's secretive execution chamber Inside Japan's secretive execution chamber The media were allowed to see the secret execution chamber for the first time during a tour in 2010 AFP/Getty Images Inside Japan's secretive execution chamber Prisoners meet with a chaplain in a room next to the execution chamber AFP/Getty Images Inside Japan's secretive execution chamber (EDITOR'S NOTE: JAPAN'S JUSTICE MINISTRY REQUESTS THAT THESE PICTURES NOT BE CROPPED FOR SECURITY REASONS) This photo taken during a media tour conducted by Japan's Justice Ministry on August 27, 2010 shows some of the rooms at the Tokyo detention house in Tokyo. Japan, one of the few industrialised democracies to maintain the death penalty, threw open the doors to its mystery-shrouded execution chamber for the first time to media. AFP PHOTO / JIJI PRESS (Photo credit should read JIJI PRESS/AFP/Getty Images) AFP/Getty Images Inside Japan's secretive execution chamber (EDITOR'S NOTE: JAPAN'S JUSTICE MINISTRY REQUESTS THAT THESE PICTURES NOT BE CROPPED FOR SECURITY REASONS) This photo taken during a media tour conducted by Japan's Justice Ministry on August 27, 2010 shows some of the rooms, including the execution room (R), inside the Tokyo detention house in Tokyo. Japan, one of the few industrialised democracies to maintain the death penalty, threw open the doors to its mystery-shrouded execution chamber for the first time to media. AFP PHOTO / JIJI PRESS (Photo credit should read JIJI PRESS/AFP/Getty Images) AFP/Getty Images Inside Japan's secretive execution chamber A view through the curtain to the execution chamber AFP/Getty Images Inside Japan's secretive execution chamber An execution room at the Tokyo detention house AFP/Getty Images Inside Japan's secretive execution chamber Japan is one of the few industrialised democracies to maintain the death penalty AFP/Getty Images

Executions in Japan are shrouded in secrecy with prisoners typically given only a few hours’ notice, while some are given no warning at all. Their families are usually notified about the execution only after it has taken place.

Shoji was convicted of raping and killing Hiroko Hayashi, 54, and killing Fumiko Osawa, 42, in Kanagawa Prefecture in 2001, according to Japan Times.

Suzuki was found guilty for the rape and murder of Nana Kubota, 18, the killing of Toshiko Onaka, 62, and the attempted rape and murder of Keiko Fukushima, 23, between December 2004 and January 2005.

Justice minister Takashi Yamashita said at a news conference after the executions that the decision was made “following careful deliberation over whether there were any grounds for suspending the execution.”

“Sexual assault, including rape, is an unforgivable crime in itself,” he added. ”These cases were particularly harrowing, as the criminals also murdered their victims.”

Last year Japan executed 13 members of the doomsday cult that carried out a sarin gas attack on the Tokyo subway in 1995.