Israel's prime minister has warned Hamas it will end the ceasefire in Gaza and resume intense fighting if the Palestinian group "does not return our hostages by Saturday noon".

Benjamin Netanyahu said he had ordered Israeli forces to amass inside and around Gaza in response to Hamas's announcement that it was postponing freeing more hostages until further notice.

Netanyahu did not specify whether he was demanding the release of all 76 remaining hostages, or just the three due to be freed this Saturday - but a minister said he meant "everyone".

Hamas has accused Israel of violating the three-week-old ceasefire deal, including by blocking vital humanitarian aid - a claim Israel has denied.