Some residents are worried about returning to their compounds
Expatriates in Saudi Arabia have been telling the BBC about the horror of witnessing the bomb attacks - and their fears about life in the Saudi capital.
Some are thinking of leaving the exclusive complexes in the eastern suburbs of Riyadh, saying they no longer feel safe.
Eyewitnesses said they initially thought they were hearing thunder or the release of firecrackers before realising they were coming under attack.
Others talked about seeing the bloodied bodies of people lying on the ground, after an explosion that lit up the night sky.
A 34-year-old Jordanian engineer, called Momen, believes the car bombers tailgated his guests into the heavily-secured al-Hamra compound at about 2300 (2000 GMT).
"We knew that a truck had got through the main gates and into the heart of the compound. We heard a burst of gunfire and I went out thinking I should see what was going on," he told BBC News Online.
"I thought I heard a hand grenade, then there was an enormous explosion which shook the house. A 100 metre column of fire shot up into the sky, there was smoke, black smoke... it was horrible."
Momen said he and his guests managed to escape without injury, but he is now looking for somewhere else to live.
"I've only been at al-Hamra for two months, but I don't think I'll be going back... it's just not safe."
Another expatriate, identified only as Stuart, who lives a kilometre away from one of the hit compounds says one of his friends found body parts in their swimming pool this morning.
He says compound residents will be re-thinking their housing arrangements after these attacks.
"The whole idea of putting foreigners together in compounds 'for their safety' clearly will have to be re-addressed when you've got suicide bombers who shoot and kill their way into compounds," he said in an e-mail to BBC News Online.
Scottish worker, John Gardiner, said he was on his way to bed when he first heard what he thought was firecrackers before realising it sounded more like gunfire.
"When the bomb blast went off, all the internal doors were blown off their hinges, all the windows were blown in, and I was blown on to my back," he said, adding that his closed curtains protected him from flying glass.
Nick Holt-Kentwell, a Briton working in Saudi, said: "At first of course you think it's thunder and everybody comes out of their houses and then we realise after a short time that it was actually an explosion
on another compound which was very close to us."
He said that westerners had been on a higher state of alert since the war in Iraq.
"We've been taking the advice of the embassy not to go into the shopping centres ... generally speaking there has been a greater police presence in Riyadh," he said.
"The fact that we're seeing attacks on our actual homes, and particularly vicious attacks - it just makes you wonder, where are you safe in the kingdom of Saudi Arabia?" he told BBC News Online.