The Israeli army has entered the Gaza Strip as it escalated its offensive on the eighth day of operations.

A column of tanks entered the besieged territory though the Beit Hanoun crossing shortly after nightfall on Saturday, as the Israeli cabinet said it had called up about 9,000 reservists as part of its preparations.

Alan Fisher, Al Jazeera’s correspondent on the Israeli-Gaza border, said that he had witnessed the movement of tanks and armoured vehicles in the area.

Iraqi secret police believed that the notorious Palestinian assassin Abu Nidal was working for the Americans as well as Egypt and Kuwait when they interrogated him in Baghdad only months before the Anglo-American invasion of Iraq. Hitherto secret documents which are now in the hands of The Independent – written by Saddam Hussein’s brutal security services for Saddam’s eyes only – state that he had been “colluding” with the Americans and, with the help of the Egyptians and Kuwaitis, was trying to find evidence linking Saddam and al-Qa’ida.

Brigadier-General James Ellery CBE, the Foreign Office’s Senior Adviser to the Coalition Provisional Authority in Baghdad since 2003, confirmed the critical role of Iraqi oil reserves in potentially alleviating a “world shortage” of conventional oil. The Iraq War has helped to head off what Brigadier Ellery described as “the tide of Easternisation” – a shift in global political and economic power toward China and India, to whom goes “two thirds of the Middle East’s oil.”

If it wasn’t clear before it should be now: the Bush Administration can’t afford to attack Iran. With gas already at $4 a gallon and rising almost every day, Iran figuratively and literally has the United States over a barrel. As much as the Administration is tempted, it is not about to test Iran’s promise to “explode” the Middle East if it is attacked.

The Iranians haven’t been shy about making clear what’s at stake. If the U.S. or Israel so much as drops a bomb on one of its reactors or its military training camps, Iran will shut down Gulf oil exports by launching a barrage of Chinese Silkworm missiles on tankers in the Strait of Hormuz and Arab oil facilities. In the worst case scenario, seventeen million barrels of oil would come off world markets.

The Bush Administration was wrong about the benefits of the war and it was wrong about the costs of the war. The president and his advisers expected a quick, inexpensive conflict. Instead, we have a war that is costing more than anyone could have imagined.

The cost of direct US military operations - not even including long-term costs such as taking care of wounded veterans - already exceeds the cost of the 12-year war in Vietnam and is more than double the cost of the Korean War.