JERUSALEM, Mar 10 (IPS) - Israeli troops and tanks have left Gaza and are poised on the border of the coastal strip. Hamas militants have largely ceased bombarding southern Israel with their rockets.

After the latest round of Mideast bloodletting, in early March, in which over 100 Palestinians were killed, four Israeli soldiers died and Palestinian rockets for the first time slammed into a major Israeli city, a tense quiet has descended on the area.

But few believe it is more than a temporary lull in the ongoing warfare between Israel and Hamas, which has controlled Gaza since violently routing the more moderate Fatah movement in June last year. It seems almost inevitable that some time in the coming weeks Israel will carry out a targeted assassination of Hamas militants in Gaza, or a rocket fired from the strip will slam into a home in Israel causing casualties, and again the violence will erupt.

The question being asked, however, is whether Israel will launch a major, wide-scale military operation in Gaza aimed at toppling Hamas and ending the rocket fire. The operation in early March, in which hundreds of troops backed by armoured vehicles and warplanes moved on populated areas in northern Gaza in a bid to target those firing the rockets and destroy rocket stockpiles, was a limited operation.

News has begun trickling out in recent days of "new understandings" indirectly forged between Israel and Hamas, with the assistance of Egyptian and U.S. mediation. The basic formula: No rocket fire on Israel by Palestinian militants and no attacks by the Israeli military in Gaza.

A recent statement by Israeli Prime Minister Ehud Olmert seems to back up these informal rules of engagement. "If they don't fire Qassams (rockets) at us, we won't attack in Gaza," he said.

In the last few days, the understandings seem to be holding. Only three rockets have been fired into Israel compared with 50 a day when the fighting was raging in the first few days of March. The Israeli military, for its part, has withdrawn all troops from Gaza and has also stopped carrying out aerial attacks on Palestinian militants in the strip.

A new balance of deterrence seems to have emerged: if Israel targets Hamas militants, the Islamic movement will fire rockets into Israel, including at a major Israeli city. For the first time, during the latest round of fighting, Hamas fired longer-range, Iranian-supplied Grad missiles, hitting the populated neighbourhoods of the port city of Ashkelon. Located some 10 kilometres north of Gaza, it his home to 120,000 people. Until now, Hamas had confined its rocket fire to smaller Israeli communities closer to Gaza.

For Israel's part, it has made clear to Hamas what the price will be if it again hits Ashkelon: more casualties after all the Palestinians killed and hundreds injured in just five days during the Israeli incursion into the strip.

Olmert's options appear limited. Besides the fear of incurring heavy losses if Israel does launch a major operation in Gaza, which would require guerrilla combat in densely populated towns and refugee camps with their narrow alleyways, there is no obvious exit strategy for the Israeli leader.

If Israel does succeed in significantly undermining Hamas during an extended operation, who will fill the vacuum in Gaza? The Fatah forces of Palestinian President Mahmoud Abbas, who were routed by Hamas militants last year, are in no state to retake control.

The possibility of an international peacekeeping force moving into Gaza also seems remote. It is difficult to see too many countries being prepared to place their troops in the crossfire between Israel and Hamas.

There is also no guarantee that after the operation ends -- it could last weeks and maybe even months -- and Israeli troops pull out of Gaza, the rocket fire won't resume. In the hours after Israel withdrew its troops from Gaza following the latest incursion, Hamas militants launched a barrage of Qassams before ceasing the rocket fire, and declared victory. Olmert cannot be certain that scenario won't be repeated after a major ground incursion.

Israel did not launch any military reprisals after a Palestinian gunman walked into a Jewish religious seminary in Jerusalem last week and opened fire, killing eight teenagers who were studying in the seminary library. Part of the reason Israel did not retaliate was because there was no clear claim of responsibility for the attack. Hamas officials said the shooting was "revenge" for the Israeli operation in Gaza, but did not claim responsibility.

But if there is another attack, or there are casualties in a rocket strike on Israel, or Israel kills Hamas militants in an aerial strike, the brittle calm that has descended in the last few days will be shattered. What's more, despite the reservations Olmert has about a wide-scale ground operation, if the rockets again slam into Ashkelon and there are casualties, he may ultimately succumb to public pressure that will inevitably mount for a major ground push into Gaza. (END/2008)