Dr Salih, the prime minister of the Kurdish regional government in the city of Sulaimaniyah, is known to favour close co-operation with America. For many years he was a Kurdish representative in Washington. He was uninjured in the attack.

He was returning to his house on Tuesday afternoon when the three gunmen opened fire. They killed the head of his private office and four bodyguards before two of them were shot dead and a third was wounded and captured, according to reports from the region.

Threats by President George Bush and senior members of his administration to overthrow President Saddam by armed force are alreadybeginning to destabilise Iraqi Kurdistan, where leaders have tried to strike a balance between the Iraqi dictator and his enemies. The Iraqi government is anxious that America might use the Kurds as its local allies against Baghdad, just as it used the Northern Alliance so successfully in Afghanistan last year.

Earlier this year the CIA appeared to give credibility to those fears when its agents were reported to have inspected three airfields in Iraqi Kurdistan that could be used by an American force. America and Britain currently fly patrols over the region to deter Iraqi military intervention.

Dr Salih, an affable, cultivated man who speaks excellent English, is a member of the Patriotic Union of Kurdistan, which controls the eastern part of Iraqi Kurdistan.

The party, led by its founder, Jalal al-Talabani, is more sympathetic to joining an American crusade against Saddam than its rival, the Kurdistan Democratic Party, which controls the western part of Iraqi Kurdistan. The KDP fears that the Kurds will once again be used as cannon fodder against Baghdad.

The attempt to kill Dr Salih is in keeping with Saddam Hussein's past record of assassinating leaders, notably those of the Shia Muslim community in southern Iraq, before they can become a threat.

One Iraqi analyst suggests that the Iraqi leader might have been angered by an interview given by Dr Salih in a US publication in which he suggested that Baghdad had links with al-Qa'ida. It is also possible that Kurdish Islamist groups, who dislike Dr Salih because of his secular outlook, might have been involved in the assassination attempt.

Baghdad is doing everything it can to make sure it is prepared for an Americanonslaught. The security and intelligence agencies have moved out of their traditional headquarters to secret locations. The regular army, incontrast to the élite Republican Guard, is normally kept short of ammunition to prevent it launching a coup but has now been issued with substantial supplies.

The Iraqi government evidently thinks an Americanattack will, as in the Gulf War in 1991 and in Afghanistan last year, be preceded by a prolonged aerial bombardment. President Saddam has told people to save food, while petrol is being stockpiled in small dumps around the country in case refineries are destroyed.

The attempt to kill Dr Salih shows the political temperature in Iraq is rising steadily.

American officials hope parts of the army might defect when they realise Washington is determined to overthrow the regime. They admit, however, that this is unlikely to take place until there is a prolonged bombing offensive. The attack on Dr Salih may be Baghdad's way of showing that it intends to strike at its enemies before they become dangerous.