"The initial investigation shows that Saud al-Utaibi and Abd al-Karim al-Mijati are among those killed," Interior Ministry spokesman Brigadier Mansur al-Turki said.
"We cannot declare this officially until we finish the verification process," he said, adding that the ministry would release an official statement later on Thursday confirming the identities of those killed.
Al-Mijati and al-Utaibi are numbers four and six respectively on the kingdom's most-wanted list of 26.
Saudi authorities on Wednesday hailed the killing of wanted al-Qaida member Abd al- Rahman al-Yazji in the capital a day after 14 armed men were killed in a three-day firefight between security forces and insurgents in al-Qasim region, north of Riyadh.
Five wounded among the insurgents were captured while a sixth surrendered. Fourteen security personnel were wounded.
Al-Yazji, a Saudi national who ranked 23rd on the list, was tracked down to a southern industrial neighbourhood of Riyadh before he was killed, the ministry said.
"The initial investigation shows that Saud al-Utaibi and Abd al-Karim al-Mijati are among those killed"
Brigadier Mansur al-Turki,
Saudi Interior Ministry spokesman
If the deaths of al-Utaibi and al-Mijati are confirmed, only three of Saudi Arabia's most-wanted insurgents remain on the run. The others have all been killed or captured.
The fate of al-Qaida's commander for the Arabian peninsula, Salih al-Ufi, is still not clear.
Saudi-owned media and a spokesman for the London-based opposition group, the Movement for Islamic Reform in Arabia, said al-Ufi was among the dead.
This week's clashes were the bloodiest in the security forces' nearly two-year-old campaign against insurgents.