RAMALLAH, PALESTINIAN TERRITORIES: Hundreds of Palestinians in Israeli jails launched a hunger strike Monday following a call from leader and prominent prisoner Marwan Barghouti, a movement that could mark a serious challenge to Israeli authorities if sustained. The hunger strike was called for in connection with Palestinian Prisoners Day, observed annually, but also ahead of commemorations this summer marking 50 years since the 1967 Six Day War and the start of Israel's occupation. Hunger strikes by Palestinian prisoners occur regularly, but rarely on such a large scale.