A disagreement between Israel and Hamas over a hostage is preventing hundreds of thousands of displaced Palestinians from returning to their homes in northern Gaza, putting pressure on a fragile week-old truce.

Eight of the remaining hostages set to be released by Hamas in the first phase of a ceasefire agreement with Israel are dead, according to an Israeli government spokesperson.

The Palestinian Islamist group Hamas has handed over to mediators a list showing that 25 Israeli hostages are still alive, out of 33 scheduled for release, an official of the group told Reuters on Monday.