A militant spokesman said Israel had kept displaced Palestinians from returning to northern Gaza, targeted Gazans with shelling and blocked aid.

Hamas says it will delay the further release of hostages in the Gaza Strip after accusing Israel of violating a fragile ceasefire that now faces its most serious crisis since it began three weeks ago.

Stalling the next release of hostages from the Gaza Strip, scheduled for the coming weekend, raises new challenges for the already tenuous six-week truce and chances for a lasting end to the war.