"We are looking at when is the right moment for a ceasefire," said the source, who spoke on condition of anonymity.

The source added that Israel was evaluating whether its objective of degrading the fighting capacity of Gaza's Hamas rulers had been achieved.

"The question is whether Hamas understands the message" that its rocket barrages towards Israel cannot recur, added the source.

Israel's massive bombardment of Gaza began on May 10, shortly after Hamas launched rockets towards Jerusalem in response to actions by Israeli police at the flashpoint Al-Aqsa mosque compound, Islam's third holiest site.

The military official said Israel had decided to go beyond narrow retaliation in its response to the Hamas rocket fire.

"We took it as an opportunity to reduce Hamas's capacity," the source said.