Leading article: There is only one route out of this bloodshed

Yesterday was another black day for the Middle East. Israel ordered fresh air strikes on southern Lebanon and stepped up operations in Gaza. Hizbollah rockets slammed into the Israeli coastal city of Haifa. A British aircraft carrier was dispatched to evacuate Britons stranded in Lebanon. A full-scale regional war seems an increasingly possible outcome.

What the evolution of this crisis demonstrates is that a "show of force" in this volatile region can never be justified. The desire of the Israeli Prime Minister, Ehud Olmert, to prove his credentials as a strong leader was what lay behind Israel's move into Gaza. It was also behind the bombing of Beirut international airport. But all Mr Olmert has succeeded in doing is painting his government into a corner. Each act of violence by the Israeli military has so far been met with an equally violent response. Neither Hamas nor Hizbollah has surrendered in the face of Israel's overwhelming military superiority. And who can now predict where this will end? Are we to see Israeli troops in southern Lebanon once again? Israel claims the strings of Hamas and Hizbollah are being pulled in Damascus and Tehran. Does that mean air strikes on Syria - or even Iran - are a possibility?

Nothing can be discounted. So hard-line has been the rhetoric from the Israeli government that there is now no obvious way for it to climb down. A prisoner exchange was ruled out from the first. And neither the Hamas militia, nor Hizbollah, is likely to give up the Israeli soldiers they captured without something in return. The only outcome at the moment seems an escalation of violence.

It is almost incredible to recall that this crisis stems from the abduction of a single Israeli soldier three weeks ago. It is also incredible to remember that Mr Olmert was elected earlier this year on a platform of consolidating the borders of Israel. Now Israeli military expansion is on the agenda again. This is not a strong position for Mr Olmert. Meanwhile, it seems support for Hizbollah has been bolstered in Lebanon by the Israeli bombings. The same can be said for Hamas. This should not come as a surprise. Collective punishments, of the type Israel has visited on the citizens of Lebanon and Gaza, have always had a tendency to rally support for insurgent groups.

Of course, it is possible to sympathise with the Israeli situation. The rocket attacks from Gaza never stopped, despite disengagement. And the abductions of Israel soldiers were unacceptable, as was the Hizbollah incursion across the recognised Israeli border that enabled them to carry this out. It is also highly likely that Syria and Iran are stoking the flames of the crisis and arming Hizbollah, as Israel claims. But in an asymmetrical military situation - which this remains - it is incumbent on the stronger party to show restraint, especially in operations that have a high probability of resulting in civilian casualties. Israel has not done so. And we are seeing the results now in a crescendo of bloodshed.

The leaders of the G8 Summit in St Petersburg were right yesterday to demand a United Nations-supervised ceasefire. When this crisis began it was a narrow question of Israel's relationship with Hamas. It has now become a question of stability throughout the region. There must be international pressure on Syria to disarm Hizbollah. There must also be pressure on Israel to halt its operations. The outside world must engage once again.

Although the splits in opinion that have emerged in the G8 meeting do not augur well, international diplomacy remains the only escape route. Any side that will not countenance a negotiated settlement - whether in Lebanon, Syria, Gaza or Israel - must be considered an enemy of peace.