(CNN) Israeli authorities early Sunday released an often-detained member of a Palestinian militant group after he spent more than 11 months in jail.
Khader Adnan of Islamic Jihad was turned over at a West Bank checkpoint before being taken to Jenin Hospital for medical tests.
The deal to release him was struck two weeks ago on June 29, ending a 55-day hunger strike. Adnan first gained international attention for a 66-day hunger strike that ended in February 2012.
He was held under a controversial Israeli military procedure known as "administrative detention" that allows Israel to hold detainees indefinitely on security grounds. The process also allows for detention based on secret evidence, and there is no requirement to charge the detainees or to allow them to stand trial.
Adnan has spent six years in Israeli jails under administrative detention. This is the 10th time he's been held without being charged.
The militant group refers to Adnan as a West Bank leader of the Palestinian Islamic Jihad, an Iranian backed militant group that has killed scores of Israelis in suicide bombings and rocket attacks.
In 2012, Amnesty International issued a report detailing the human rights abuses associated with administrative detention, which it said Israel uses to "suppress the legitimate and peaceful activities in the occupied Palestinian territories."
Amnesty called for the "immediate and unconditional release" of prisoners held under this policy.
There are more than 500 Palestinian prisoners held under administrative detention according to the Palestinian center for human rights.