Israeli Prime Minister Ehud Olmert says border crossings with Gaza will not be fully opened until a captured Israeli soldier is freed.
Egypt is trying to mediate a long-term truce between Israel and Hamas, following Israel's bruising offensive in Gaza to stop Palestinian rocket fire.
Hamas insists that border crossings must be opened to allow goods into Gaza as part of the deal. Olmert said the soldier, Sgt. Gilad Schalit, held since June 2007, is Israel's first priority.
Olmert spoke on Sunday to US Jewish leaders. Referring to the Hamas demand, he said, "Hamas must think twice if they think we will open borders before Gilad Schalit is returned home and healthy."
Olmert said Israel would pay a stiff price, freeing militants from Israeli prisons.
