Foreign Minister Tzipi Livni said Sunday that Israel was required to respond to every rocket fired from the Gaza Strip, adding that a truce marked by constant attacks was meaningless.

"As long as Hamas continues to operate with terror from Gaza, Israel will operate with its own means," Livni said during talks with her visiting Austrian counterpart.

"The government is responsible for the citizens of the state. It needs and must respond to terror through military means," she added. "We cannot allow Gaza to remain under Hamas control."

Hamas' leadership in Damascus announced earlier Sunday they the militant group would not renew its six-month-old truce with Israel in the Gaza Strip, set to expire on Friday.

"There will be no renewal of the calm after it expires," the statement quoted Khaled Meshal, the Islamist group's exiled leader, as telling a Hamas television station.

However, officials of the Palestinian Islamist group based in the Gaza Strip took a less definitive line, leaving open the possibility of negotiation before the Egyptian-brokered pact ends.

"The truce will not renewed as long as there is no real and full Israeli commitment," one Gaza official said in response to the report of Meshaal's remarks to Al-Quds Television.

But he added: "If the occupier's position changes, it will be studied."

A spokesman for Prime Minister Ehud Olmert said Israel was prepared to maintain the truce, but would not do so if Hamas continued to violate it by allowing militants to fire rockets at the Negev.

"Israel has been, and continues to be, ready to abide by the understandings negotiated through Egypt," said government spokesman Mark Regev.

"But it is clear that we won't be doing so unilaterally," the spokesman he said, citing what he called Hamas's "daily grave violations of those understandings".

Israel predicts tense week as truce nears end

Israeli defense officials have predicted that the coming week will be tense along the Israel-Gaza border, as the cease-fire (tahadiyeh in Arabic) between Israel and Hamas came to an end.

Major General Amos Gilad, the head of political military policy at the Defense Ministry, flew to Cairo on Sunday morning to meet with top Egyptian intelligence officials to discuss the future of the truce.

Vice Premier Haim Ramon blasted Barak on Sunday for sending Gilad, saying he should have held off until after a government decision on whether to pursue a ceasefire extension.

"Ministers who supported the cease-fire in previous votes have said it is out of order to conduct negotiations before the government decides on its stance, on the basis that it will present the government with a fait accompli."

Barak replied that the meetings are routine and have nothing to do with the impending end to the cease-fire. He added that Israeli policy would only change via the appropriate channels.

Defense ministry officials told Haaretz that Israel has made it clear to Hamas, via Egypt, that it would not agree to a continuation of the current situation and that it requires a return to a full ceasefire.

The assumption in Jerusalem is that while Hamas will seek to extend the cease-fire, the Islamic group will try to alter the terms of the agreement to allow it to continue firing rockets and mortars at the western Negev at will.

In the coming days, Israeli defense officials expect Hamas to increase the number of provocative attacks against Israeli targets, in an attempt to force Israel to accept worsened cease-fire conditions from Jerusalem's point of view. Defense Minister Ehud Barak, who backs the extension of the cease-fire, bases his position - in part - on a document prepared by his ministry, which argues that Israel's interests are best served by extending the cease-fire.

There were three days of quiet on the Israel-Gaza border last week, presumably because of the Muslim festival of Eid al-Adha. The moment the festival ended, on Friday, the rocket attacks resumed, and three Qassams landed in open spaces in the western Negev. No one was injured in the attacks. The daily launching of rockets resumed in mid-November, after an IDF operation to locate and destroy tunnels ended with six armed Hamas men being killed.

The unwritten cease-fire agreement that Egypt brokered in June between Israel and Hamas does not specify an expiry date. Hamas has said in the past that the agreement is valid for six months, and that its extension depends on expanding the cease-fire to the West Bank. It now appears that Hamas will not insist on this demand, but, in order to avoid domestic criticism for bowing to pressure from Israel, it will not officially accept that there is any cease-fire from next week.

At the same time, Hamas will continue to fire a relatively small number of rockets and will not prevent other organizations from doing the same. The IDF believes that Hamas will focus most of its efforts on the "perimeter" - the 500-meter strip of land on the Gazan side of the border fence. The organization's goal is to have Israel become accustomed to Hamas' presence in this area, while also making the IDF pay a price for any attempt to attack militants inside this buffer zone by firing large numbers of rockets and mortars.

In so doing, Hamas is hoping to recreate the same conditions that Hezbollah created along Israel's border with Lebanon, from the time that Israel withdrew from Lebanon in May 2000 until the outbreak of the Second Lebanon War in July 2006.

The system works thus: The organization establishes a permanent presence along the perimeter fence, including snipers, roadside bombs and mortars. Israel, for its part, will refrain from any offensive or preventative measure (such as dismantling bombs) in Palestinian territory for fear of becoming embroiled in a bloody conflict.

Hamas hopes these new conditions will allow it to extract an additional relaxation of the Israeli blockade of Gaza and greater freedom of travel for Gazans seeking to cross over the Rafah border, which is currently controlled by Egypt.

Barak: I don't regret a single second of the cease-fire

Barak said Saturday, at a panel discussion Holon, that he does not regret "a single second of the cease-fire in the south, which followed seven years of rocket attacks."

"When we need to act," he added, "we will act. I have seen on more than one occasion how certain people are too quick to make decisions on national security and then to try and cover their mistakes."

Barak's position is also based on another document drawn up my members of his department recently, which details the advantages of the cease-fire from an Israeli perspective. That said, the authors of the document admit that Israel has not completed the defensive measures that it had planned in the Jewish communities adjacent to the Gaza Strip or the Iron Dome missile defense system.

Barak added that the fate of kidnapped IDF soldier Gilad Shalit is a key element in Israel's considerations for extending the cease-fire and argues against the proposal to launch an all-out offensive in Gaza at the current time. Barak also criticized Foreign Minister Tzipi Livni for her comment last week to Tel Aviv high-school students that "it is not always possible to bring soldiers home."

"I am not sure I understand what the foreign minister meant by that," Barak said. He added: "We have a moral responsibility to secure the release of a kidnapped soldier and to bring him home safe and sound. Not at any price, but at any price that is reasonable and feasible. We will have to make some difficult decisions before getting Shalit back, but I am willing to make those decisions to ensure his safe return."