PARIS -- With the ending of the truce between Israel and Hamas, Gaza is now one of the Middle East's most dangerous flashpoints. U.N. Secretary General Ban Ki-moon has issued a cry of alarm, while Tony Blair, the Quartet's Middle East envoy, has urged Israel to defuse tensions by lifting the siege of Gaza.

Everyone is aware that it would take only a spark - such as a Qassam rocket landing on a house in Sderot - to trigger a full-scale war. The paradox is that neither side really wants this to happen.

Yet, on Dec. 19, the Izzedine al-Qassam brigades, the armed wing of Hamas, announced that the truce would not be renewed, while a spokesman for Israel's Prime Minister Ehud Olmert said that the truce had "lost all meaning."

Israel's Defense Minister Ehud Barak is, however, well aware of the military and political risks of a full-scale military operation against the strip. He nevertheless faces continual sniping, and accusations of excessive caution, from rivals such as Tsipi Livni, head of Kadima, not to mention from the hardline Likud leader, Benjamin Netanyahu.

In turn, Ismail Haniyeh, head of the Gaza government, also faces pressure from more extreme elements in his own camp - from armed groups eager to punish Israel and from Khaled Meshaal, the Hamas political leader in exile in Damascus.

Israel and Hamas blame each other for the breakdown of the truce. Israel complains that rocket attacks on southern Israel never really ceased, while Hamas says that Israel did not fulfill its obligations under the truce since, far from easing its paralyzing siege of Gaza, it intensified it, reducing the territory to abject poverty.

According to the United Nations, 76 percent of the population of 1.5 million in Gaza is now in need of urgent humanitarian assistance.

Having sealed the crossing points, Israel has forced the besieged territory to depend for its survival on goods smuggled in from Egypt through hundreds of clandestine tunnels. And Egypt refuses to open the Rafah crossing point because it suspects that Israel would like to transfer to Egypt full responsibility for the troublesome Gaza Strip.

In any event, Egypt has a deep-seated distrust of - and distaste for - the Islamic resistance movement (Hamas), which is closely linked to the Muslim Brotherhood opposition inside Egypt. Cairo also accuses Iran, its regional rival, of manipulating the Palestinian cause for its own ends. This has led to a sharp deterioration in already strained Egyptian-Iranian relations.

Egypt, nevertheless, brokered the Israel-Hamas truce in the first place, six months ago. But, unable to draw up binding terms, it had to make do with half-hearted undertakings from both Israel and Hamas. This was because the two parties refused to grant each other recognition, let alone legitimacy. For Israel, Hamas is a "terrorist organization," while for Hamas, Israel is the "Zionist enemy," which usurped Arab Palestine.

However, if any sort of Israeli-Palestinian peace settlement is to be reached - and U.S. President-elect Barack Obama will come under international pressure to give the conflict high priority when he takes office in January - both sides will need to change their tune.

To win international support, Hamas needs to restate publicly the message it gave last April to former U.S. President Jimmy Carter, and more recently to Yves Aubin de La Messuzière, a former senior French diplomat. This message was that Hamas no longer adhered to its 1987 charter, which called for the destruction of Israel, but would support the creation of a Palestinian state within the 1967 borders - provided this solution was approved by the Palestinian people in a referendum.

Such a statement - if repeated with sufficient clarity and authority - would put Hamas in line with the international consensus and open the door for a dialogue with the European Union, if not yet with the United States.

If Israel, in turn, wants peace, it will need to recognize that Hamas is an unavoidable part of the Palestinian equation and cannot be excluded. Israeli politicians, preparing for general elections on Feb. 10, are well aware that their country is likely to face growing pressure in the coming year to come to terms with both the Palestinians and Syria.

Preliminary signs of this pressure are already in evidence. They include the U.N. Security Council Resolution of Dec. 16, sponsored by both the United States and Russia, which expresses support for the creation of a Palestinian state, living side by side and at peace with Israel; and, an EU document recommending setting up an international peacekeeping force for the Palestinian territories, including a fund to compensate Palestinian refugees.

Another sign of hardening Western opinion against Israeli settlement expansion was a warning to Britons last week by the British Foreign Office not to buy land or houses in West Bank settlements or the Golan Heights, as any peace deal could have consequences for such property.

Gaza could turn out to be one of Obama's biggest problems. He will have to act fast if an explosion is to be avoided, which could durably set back the cause of Middle East peace.