The International Committee of the Red Cross says it fears for the life of a prominent Palestinian prisoner who has been on a hunger strike for 48 days.

It's the second marathon hunger strike for Khader Adnan, an activist in the militant Islamic Jihad group, who has been held without charge for almost a year. In a previous stint in administrative detention in 2012, Adnan went on a 66-day fast to press for his freedom, sparking weekslong hunger strikes by hundreds of Palestinian detainees.

The Red Cross said Monday that Adnan's life is "at immediate risk" and that his family must be allowed to visit, in line with international conventions.

Sivan Weizman of the Israel Prison Authority says Adnan is in an Israeli hospital. She declined comment on his condition.