Palestina - A Palestinian prisoner who has been on hunger strike for 54 days while being detained without trial by Israel is in a critical condition, medical charity Physicians for Human Rights says.

Khader Adnan has not had food since mid-December, when Israeli security forces raided his West Bank home.

It is thought to be the longest hunger strike by a Palestinian prisoner.

Mr Adnan is widely believed to be a leader of the Palestinian militant group, Islamic Jihad.

Israel has designated IJ a terrorist organisation.

Doctors from the PHR organisation say they fear Mr Adnan is close to death.

"His situation is critical," said PHR spokeswoman Hadas Ziv.

"He is shackled to his bed by both legs and one arm. His family who visited him this week believe he has lost a third of his body weight."

A doctor from PHR was able to visit Mr Adnan in hospital in northern Israel this week, but cannot comment on the specifics of his case due to patient confidentiality.