Erdogan's comments today came a day after US lawmakers called on Turkey and Egypt to help end the conflict in the Middle East.
Turkey's Foreign Minister Ahmet Davutoglu is set to join an Arab League delegation that will travel to Gaza to try to broker a cease-fire.
Erdogan accused Israel of inhumane acts at a meeting gathering religious leaders and added: "That is why I say Israel is a terrorist state."
Israel insists the offensive is meant to quell Hamas rocket fire on Israel.
Turkey's ties to Israel collapsed over a deadly raid by Israeli troops on a Turkish aid ship bound for Gaza in 2010.
Ankara: Turkish Prime Minister Recep Tayyip Erdogan has called Israel a "terrorist state" for its offensive in the Gaza strip now in its sixth day.
First Published: Monday, November 19, 2012, 23:21