An Israeli official quoted Olmert as telling a parliamentary panel: "We are in the midst of a combat action. What happened in recent days was not a one-time event.
"The objective is reducing the rocket fire and weakening Hamas."
Hamas has welcomed the Israeli withdrawal and said it signalled a "victory" for the Palestinians.
Mahmoud Abbas, the Palestinian president, had suspended all contact with Israel over its assault that left at least 116 Palestinians dead, including 22 children and 12 women.
Overnight, Israel attacked Gaza from both land and sea with naval ships shelling the territory.
The EU, UN and the Catholic pope joined Abbas on Sunday in demanding an immediate halt to the violence.
Israel says the raids are in self-defence, aimed at curbing homemade rockets being fired over the border from the Hamas-controlled territory.
It has threatened to intensify its ground and air campaign, despite allegations it is using excessive force.
Nine rockets slammed into southern Israel, wounding four people on Sunday, Israeli ambulance workers said.
Slovenia, the current EU president, issued a statement on Sunday condemning Israel's attacks as Javier Solana, the European body's foreign policy chief, was dispatched to meet leaders in Israel and the West Bank.
"The presidency rejects collective punishment of the people of Gaza. Such activities are contrary to international law," the statement said.
"The presidency at the same time reiterates its condemnation of continued firing of rockets into Israeli territory and calls for its immediate end."
Ban Ki-moon, the UN secretary-general, joined his voice to growing global denunciations of the attacks that left more than 60 Palestinians dead on Saturday alone.
Addressing an emergency session of the security council in New York, Ban also called on Palestinian fighters to stop firing rockets into Israel.
He said: "While recognising Israel's right to defend itself, I condemn the disproportionate and excessive use of force that has killed and injured so many civilians, including children ... I call on Israel to cease such attacks."
"I [also] condemn Palestinian rocket attacks and call for the immediate cessation of such acts of terrorism."
Abbas designated Sunday as a day of mourning.
He ordered "the suspension of negotiations ... until [Israeli] aggression is stopped", a senior aide to Abbas said in the West Bank city of Ramallah on Sunday.
Nabil Abu Rudeina, an Abbas spokesman, said in a statement: "The negotiations are suspended, as are all contacts on all levels, because in light of the Israeli aggression such communication has no meaning."
Arye Mekel, an Israeli foreign ministry spokesman, said Abbas's decision was a mistake and expressed hope that the talks would resume "in the very near future".
The director of the United Nations Relief and Works Agency in Gaza however, told Al Jazeera the attacks on the strip were in nobody's interest.
Speaking about the situation in territory, John Ging said: "The crossing points have been closed for days. [We are] struggling to keep our food aid going - remember a million people are food aid dependent - and we're at our wits end to understand how this will lead to the peace and stability that we all so desperately need."
West Bank clashes
As Gazans mourned the dead, clashes between Palestinians and Israeli troops erupted on Sunday in the Shufat refugee camp in occupied East Jerusalem, Hebron, and Belin as well as other areas across the West Bank.
More than 40 Palestinians were injured, three of them seriously, as the demonstrators clashed with Israeli troops.
|Two Israeli soldiers were killed during clashes|
on Saturday in the Gaza Strip [Reuters]
Hundreds of West Bank residents holding Hamas and Fatah flags staged rallies and appealed for national unity in an atmosphere that is being compared to the situation at the start of the second intifada in 2000.
In Lebanon, up to 1,000 people waving Lebanese and Palestinian flags rallied near the Israeli border against the continuing attacks on Gaza.
The demonstrators, at the Fatima Gate border point near the southern village of Kfar Kila, shouted "Death to Israel" and "The blood of our sons in Palestine will not be in vain".
Egypt, meanwhile, has agreed to open the Rafah border crossing to let injured Palestinians receive medical treatment.
Responding to a request by the Palestinian Authority, Egyptian authorities permitted 250 injured Gazans to enter Egypt through the controversial crossing.