The latest terrorist bomb attacks have shaken Istanbul, but not Turkey's resolve to resist the demands of those behind them. Nor should they deflect the United States from its purpose in Iraq: to rebuild and strengthen it with democratic institutions and restore its independence.

The latest terrorist bomb attacks have shaken Istanbul, but not Turkey's resolve to resist the demands of those behind them. Nor should they deflect the United States from its purpose in Iraq: to rebuild and strengthen it with democratic institutions and restore its independence.

Yet, like all terrorist attacks, these have the power to shock and confuse. There is no denying their symbolic impact. For the first time since September 11, 2001, specifically British targets have been hit by terrorists apparently directed or influenced by al-Qaeda.

The attacks, a few minutes apart, struck at British Government and commercial interests, the consulate general and the offices of the British banking giant HSBC. Naturally that has caused an immediate review of security at British diplomatic missions and at the offices of the extensive British commercial interests around the world. While there has never been an al-Qaeda attack in Britain, the bombings in Istanbul create an immediate sense of vulnerability.

They are bound to have a similar effect on Australians' sense of security, not least because of the threats made in the wake of the similar car bomb attacks on two synagogues in Istanbul last Saturday. In a message from a group linked to al-Qaeda, the perpetrators of those outrages addressed "the criminal Bush and his Arab and Western hangers-on - in particular Britain, Italy, Australia and Japan" and threatened further attacks by the "cars of death".

It is possible that Thursday's attacks were precipitated by the heat Turkish police have applied in their search for the perpetrators of the synagogue attacks. More likely, Thursday's attacks were timed to coincide with the state visit of the US President, George Bush, to London.

At a joint press conference with Mr Bush, the British Prime Minister, Tony Blair, said: "What this latest outrage shows us is that this is war. Its main battleground is in Iraq." That is true, especially in the sense that it is vital - if the United States and its allies are to defeat the terrorists by example - to show that a modern, democratic and free Iraq is possible.

Unfortunately, these attacks also show that in the so-called war on terrorism there are other battlegrounds. They are many, and are chosen by an enemy with an endless supplies of recruits, who emerge at the moment when they are ready to murder and die in the process.

Australia has tasted the horror of this kind of warfare, in Bali. Now, as then, the response is the same. The methods of terrorism are foul and the killing of innocents always inexcusable. The demands made by terrorists must never be acceded to. The threat of terrorism must be met by the utmost vigilance against all possible attacks.

At the same time, the surest answer to terrorism is the removal of the causes of the grievances and the hatreds on which it feeds. In that sense the war in Iraq - to establish a free, strong and independent country - is indeed the main battleground. Unfortunately, there are many more, and this war will be very long.