The Israeli authorities have placed Nidal Abu Ayash, a 28-year-old mentally-disabled Palestinian man, in "administrative detention" for six months.

Abu Ayash, who hails from the town of Beit Ummar near Hebron (Al-Khalil), is now being held at Israel's Ofer Prison near the West Bank city of Ramallah.

In a statement on Monday, Luai Akka, a lawyer for the Palestinian Prisoners Society (an NGO that advocates for Palestinian prisoners' rights) said he had managed to visit Abu Ayash in prison.

The prisoner, Akka said, "doesn't know where he is; it's difficult to talk to him. He keeps threatening to commit suicide."

At one point, according to the lawyer, Abu Ayash had tried to jump off the upper floor of the prison but was prevented from doing so by other inmates.

"He is not aware of who is around him; he has not been sleeping well for months. And he lacks access to the medication he needs," the lawyer said.

"He suffers from a heart disorder that affects his brain, which means he needs special medical attention," Akka added, pointing out that the Israeli authorities were aware of his medical condition but had nevertheless designated him a "security threat".

The lawyer went on to describe Israel's policy of administrative detention -- by which suspects are held without trial or charge -- as a "vengeful policy without legal basis".