By Martin Asser
BBC News Online
The shooting deaths of two Americans in separate incidents in the days after the attack on two BBC journalists in the Saudi Arabian capital Riyadh are further reminders of the dangers now faced by foreigners in the conservative Muslim kingdom.
Saudi Arabia has won US praise this year for a crackdown on al-Qaeda
Gunmen shot dead an American man - reportedly as he parked his car - four days after an American military contractor was killed in Riyadh.
That attack followed the drive-by shooting of the BBC team in which cameraman Simon Cumbers was killed and correspondent Frank Gardner seriously injured. The journalists were on a trip to Saudi Arabia to report on the aftermath of a bloody hostage taking incident in Khobar in which 22 people died.
The killings highlight in a most uncomfortable way for the Saudi authorities that they are a long way from putting the brakes on an Islamist extremist movement that wants to cleanse the Arabian peninsula of what it sees as heresy and apostasy.
As Frank Gardner said himself in a report for the BBC last week, Saudi Arabia is not the same country that he first visited 15 years ago.
A country to which expatriates used to flock for a secure environment with excellent career opportunities is now dotted with security checkpoints and nervous guards - their fingers twitching on triggers with the expectation of attack at any minute.
The highly experienced two-man BBC team with an escort and driver from the Saudi Arabian information ministry was in al-Suwaydi - whose location a few minutes' drive from the shiny modernity of downtown Riyadh belies its deprived reality.
About half a million people live in the slum district, many of them villagers from the surrounding Nejd region, the heartland of the deeply conservative Wahhabi brand of Islam that is the founding creed of the Saudi state.
But it is also the cornerstone of al-Qaeda ideology and many inhabitants of al-Suwaydi are thought to support its Saudi-born leader Osama Bin Laden.
Gardner is a seasoned BBC correspondent
As the team were on location in this area - where few Westerners would set foot without a very good reason - a vehicle drove past and opened fire.
No-one apart from the two journalists was reported hurt and the vehicle made a clean getaway.
There have been persistent doubts about Saudi Arabia's response to the al-Qaeda threat ever since it emerged when the Islamic holy warriors led by Bin Laden emerged victorious from Afghanistan after defeating the Soviet invaders.
Theories abound as to whether it was incompetence, ambivalence or the delicacy of the Saudi authorities' position vis-a-vis the population that allowed extremist support to thrive in the kingdom.
Questions still surround the denouement of the Khobar attack at the end of last month - when three killers slipped through a security cordon imposed by large numbers of security men besieging the compound where the deaths took place.
Soldiers manning the checkpoints are distinctly nervous, their fingers on the trigger guards of their assault rifles, their faces darting through car windows
Prince Turki al-Saudi, the Saudi ambassador in London, touched on the delicacy of all-out action against al-Qaeda when he spoke to the BBC the day after the latest attack.
There are two ways of combating opponents of the Saudi regime, he told the One O'clock News; "One way is to go in with all guns blazing and arrest thousands of people, and hopefully capture two or three or four of the terrorists.
"But that is precisely what the terrorists want us to do - to antagonise the population and make it seem like it is a struggle against the whole population and not just against the terrorists."
That is why he says the Saudi authorities have taken a more "methodical" approach, in which thorough police work and international co-ordination are given precedence.
But Saudi-watchers point out that "guns blazing" is exactly the approach that the security forces have taken this last year, winning plaudits from Washington for the first time since the "global war on terror" was declared by the US following Bin Laden's attacks on 11 September 2001.
Hundreds of Islamist suspects have been arrested and there have been dozens of shoot-outs between militants and police.
But as far as it is known - in this most secretive of countries - not a single trial has been held where home truths can be aired about the militant organisations and any possible link they may have with the authorities.
Invariably the militants die in a hail of bullets and take their stories with them to their graves.
The silence in the Saudi courts mirrors the silence coming out of Washington a year ago, when the Bush administration famously blocked publication of part of a congressional report dealing with allegations of official Saudi complicity in the 9/11 attacks.
The Saudis repeatedly deny any complicity with the militants and we are left with the stark facts of what has happened in the last year.
More than 80 people killed by al-Qaeda-linked militants - Saudis, Muslim and non-Muslim Arabs, Westerners and Asians.
The deaths have shaken the long-standing sense of security in the kingdom and more recently caused worrying spikes in petroleum prices.
One of the stories Gardner and Cumbers were following before they were attacked was how expatriates in particular have begun to think about leaving a country that has hosted hundreds of thousands of them over the decades.
Lingering doubts about the authorities' willingness and ability to protect them are central to those fears that could one day drive people away.
It would be a great blow to Saudi Arabia if an expatriate exodus did occur. The country has for many years been trying to "Saudi-ise" its workforce, partly as a way of combating rampant Islamist extremism that is bred in part by the economic exclusion of large numbers of citizens of this oil-rich kingdom.
But the loss of prestige if Saudi Arabia cements the reputation as somewhere that is a "soft touch" on terrorism would be huge.