Their relationship is rooted in the American need for oil and the Saudi need for security, each has something the other badly wants

And while the constant refrain from US officials is that they are fully satisfied with the co-operation they are receiving from their close ally Saudi Arabia, it is not a view many Americans appear to share.

Newspaper columnists are complaining that the Saudis are unreliable allies, that they are too secretive and too reticent.

They say they are not giving enough help to the FBI in tracking down those responsible for the 11 September attacks against America, or in cutting off the terrorist's sources of money.

Saudi connection

Embarrassingly for the Saudis, the main suspect, Osama Bin Laden, is Saudi-born - even though the kingdom stripped him of his citizenship in 1994.

According to US officials, ten or more of the hijackers were Saudis.

And Saudi involvement does not stop there - it is widely believed that wealthy Saudis and other Gulf Arabs have for years been secretly helping to fund the Bin Laden group.

The US has sought Saudi support for its terrorism fight

Also under scrutiny has been the Saudi kingdom's links to the Taleban movement in Afghanistan.

The Saudi brand of Islam, known as Wahhabism, is not dissimilar to the Sunni puritanism practised by the Taleban and until recently, Saudi Arabia was one of the few countries to recognise and finance the Taleban regime.

While the American media are sniping at Saudi Arabia, the state-controlled Saudi media are scarcely in love with America.

Even before the 11 September, there was a sharp edge to the anti-Americanism in Saudi newspapers. Its main focus was Washington's perceived silence and passivity over the deaths of hundreds of Palestinians at the hands of the Israelis.

Muslims blamed

Saudis, like other Arabs, believed the Americans could and should be doing more to rein in their Israeli ally.

After the attacks new grievances added fuel to old ones - Saudis sensed an anti-Arab, anti-Muslim backlash in the United States.

Saudi Arabia thinks the US could do more in Israel

Some refused to believe Bin Laden was behind the attacks against America, or accused Americans of being too quick to blame Muslims.

Saudis were incensed when the mayor of New York rejected a $10m donation offered to the city as a gesture of sympathy by a wealthy Saudi prince.

The mayor took exception to the prince's call for a change in US policy towards the Palestinians - a call most Saudis would endorse.

The gulf of misunderstanding between two supposedly close allies could scarcely have been more evident.

Odd couple

For some 50 years the United States and Saudi Arabia have been the oddest of odd couples.

Their relationship dates back to World War II. It is rooted in the American need for oil and the Saudi need for security.

Each has something the other badly wants, and so far that has proved a strong enough bond to withstand periodic stresses and strains.

Saudi Arabia is home to Islam's holiest sites

It was the Americans, to British chagrin, who were the first to exploit Saudi oil in the 1930s.

It was the Americans who created and built up Aramco, the oil company which has played such a big part in the development of modern Arabia, and although the company was nationalised in the 1970s, changing its name to Saudi Aramco, its style is still unmistakeably American.

It was the United States which was, and has remained, the kingdom's main arms supplier and, in the last resort, is the country which protects it from external threat.

Separate worlds

Superficially, Saudi society has been Americanised - every visitor is struck by the skyscrapers and Cadillacs and American-style fast-food restaurants and shopping malls - and the occasional twang of American-accented English spoken by Saudis who have spent part of their youth on an American campus.

But at a deeper level it is as if Saudis and Americans lived on separate planets. In their attitudes to women and sexual morality, to democracy and human rights, the two peoples are far apart.

Giuliani rejected the Prince's money

Above all, the kingdom's deep attachment to a conservative form of Islam is something Americans, along with other Westerners, find very hard to understand.

Saudi rulers take very seriously their role as custodians of Mecca and Medina, the two holiest places in Islam.

The current crisis has created an inevitable tension between their solidarity with fellow Muslims and their strategic partnership with America.

The longer the crisis lasts, the more acute this tension will become.