The killing of five Westerners in Yanbu on Saturday has sent shockwaves through the expatriate community in Saudi Arabia. BBC News Online asked UK national Ian Billing, who works at Aramco oil company as a research geologist, what steps foreign staff have been taking.
Ian has worked in Saudi Arabia for three years
We were at work when we found out about the attack. It was my officemate - a local Saudi - who alerted me to it. He had read about it online.
It was a feeling of great shock at what was going on - we felt horrified and saddened at what had happened.
Our Saudi colleagues were totally sickened, in absolute disbelief that people who claimed to be Muslims could carry out such an attack.
Our initial thought was that it was some sort of retaliation - an outraged reaction to those photographs of the Iraqi prisoners being mistreated.
But now we think it was something deeper, more of a longer-term, planned attack.
It was particularly shocking because, being in an oil and gas company, we work in a similar field - the people who committed the act had ID cards for the company they attacked.
Degree of security
In Dhahran, we live in a double-gated compound which is the size of a small town. The outer perimeter is where the offices are and the inner area is residential.
There are three or four gates into the compound - each have their own security guards.
I have noticed they have stepped up searches in the early evenings of cars coming into the compound where I live
We have always felt a degree of security because we are a mixed community with locals and Westerners living on the same street. Anyone who launched an attack would also hit locals.
My children go to the British school, which is a few miles out of the camp.
The bus takes them everyday. The school joins on to the American embassy, so security around there is also very tight.
The day after the attacks it took them two hours to get to school with all the security cordons.
Security is sporadic here.
One day there will be police checkpoints on the road to your camp, with guards looking at driving licenses and checking car boots - but today for example they just waved us on through.
US citizens have been advised to leave Saudi after the attack
There is no real pattern to the security, although I have noticed they have stepped up searches in the early evenings of cars coming into the compound where I live.
But I have not seen a physically larger police presence around.
We have a quiet belief that there are a lot of undercover operations going on. We read the Arab News [English-language newspaper] - which keeps you up to date on operations - and you hear of plots being thwarted, gangs being chased and arrested.
It feels fairly comfortable here, as one of the most relaxed provinces and also the most prosperous.
But other nationalities are different - the Americans are more paranoid than the Brits.
You have to put it into perspective - you are far more likely to meet your end on roads into the shopping centre in Saudi Arabia than to be killed by terrorists. Road accident mortality rates here are appalling.
We have American colleagues who are convinced that there will be another terrorist attack.
We know one family taking an early summer break - the husband is staying behind but the family is being sent away to New Zealand.
Most people here have a more relaxed attitude.
We receive warden reports from the ambassador - we are on the e-mail distribution list and it always alerts us of dangers but it has been fairly quiet in recent days.
They just say keep a low profile, don't draw attention to yourself, look under vehicles if you have parked in public places.
Most of us are just careful when we go out. We go out as obvious families and are conservatively dressed - we don't go out in Union Jack T-shirts.
I have never seen hostility or aggression and never anything that makes me nervous.
Personally, I would rather stay and wait out here.
Interview by Sarah Brown