By Rob Watson
BBC security and defence correspondent
The Saudi authorities are claiming this as yet another success in their recent crackdown on al-Qaeda militants.
Security has been heightened to reassure investors
According to the Saudi security forces five men were killed after a building was surrounded in Riyadh while a sixth man was captured in a separate raid in another part of the city.
Most significantly the Saudis are making a clear link between today's operations in Riyadh and last Friday's failed suicide attack against the massive oil processing plant at Abqaiq.
They claim three of the alleged militants killed today were followed to Riyadh from Abqaiq.
So what does all this say about the Saudis' continuing campaign against al-Qaeda militants?
The authorities claim, with some justification, to have al-Qaeda on the run in the kingdom.
Only recently the Saudi ambassador to Washington, Prince Turki al-Faisal, said only a few extremists were now at large.
Certainly the Saudis can point to some notable successes.
There have been no major attacks in the kingdom for over a year and more than 100 militants have been killed by the security forces including the alleged leader of the Saudi branch of al-Qaeda.
The authorities also claim to have made strides in discouraging and preventing the recruitment of young men to the militant cause.
But there's no doubt Saudi Arabia remains a target for al-Qaeda.
An al-Qaeda statement posted on the internet this weekend claimed responsibility for last Friday's failed attempt on Abqaiq and threatened further attacks on Saudi Arabia's oil facilities.
Such attacks also remain an ambition of the organisation's two main leaders, Osama Bin Laden and Ayman al-Zawahiri, who've both urged attacks targeting what they describe as an industry that steals oil from Muslims.
Over the last few years security at the country's oil facilities has been greatly strengthened.
But analysts point out that the kingdom's oil fields and other facilities are so massive it is difficult to provide complete security.
That said, last Friday's failed attempt on Abqaiq does raise questions about the strength and capabilities of the militants.
Some analysts see the attack as lacking some of the thorough planning characteristic of al-Qaeda operations an indication that this was a hurried affair.
It's also been suggested that al-Qaeda's ranks in Saudi Arabia have been thinned by militants travelling to fight in neighbouring Iraq.
But that may prove a temporary respite for the Saudi authorities with some militants warning al-Qaeda will be stronger than ever when battle-hardened fighters eventually return home.