Doctors without Borders has accused Israel of using humanitarian aid as a bargaining chip, days after Israeli authorities cut power to the only water desalination plant left in Gaza. Yemen's Houthi rebels have vowed to resume attacks on Israeli ships travelling through the Red Sea and the Gulf of Aden, until shipments of aid are allowed back into Gaza. Meanwhile, mediators are seeking to bridge differences between Israel and Hamas, as fresh rounds of negotiations begin in Doha. Giles Gibson