TOKYO: Japan on Tuesday hanged three inmates convicted of multiple murders, including a Chinese man and another man who found his victims through an Internet suicide site, officials said.

"Executions were carried out today on three inmates who had been sentenced to death," the justice ministry said in a statement.

It identified the convicts as two Japanese men -- Hiroshi Maeue, 40, and Yukio Yamaji, 25 -- and Chinese national Chen Detong, 41, who had killed three of his compatriots and wounded three more Chinese people.

Maeue, executed in Osaka, killed three people in 2005 after he got to know them separately through an Internet website where people contemplating suicide go to meet others thinking also of ending their lives.

Maeue arranged to meet them with the idea of a joint suicide, and then choked them to death. He confessed to deriving sexual pleasure by seeing people suffocate.

Yamaji, also executed in Osaka, raped and then stabbed to death two sisters, stole their money and set fire to their apartment in 2005.

Chen, the Chinese national, was executed in Tokyo for killing three of his compatriots and injuring three more in Kawasaki, southwest of Tokyo, in 1999.

Japan is the only major industrial nation other than the United States to apply the death penalty. Japan's last executions were in January when four convicted murderers were hanged.

The death penalty is overwhelmingly supported by the public in Japan, which has one of the world's lowest crime rates.

But Japan has regularly come under fire from the European Union and campaigners over its use of the death penalty, especially its practice of hanging inmates without any prior warning to them or to their families.

Makoto Teranaka, of Amnesty International's Japanese chapter, said after the latest executions Tuesday that "this is a grave act that cannot be permitted amid international calls to suspend capital punishment".

Despite the criticism, conservative governments have stepped up the pace of executions. Last year Japan hanged 15 death-row inmates, the highest number since 1975, when the country executed 17 people.