Riyadh Daily said on Sunday security forces were scouring the capital, fearing the vehicle would be used in an attack.
"Any person who provides information leading to the capture of the vehicle will, in line with a royal decree, receive a reward of seven million riyals," Saud bin Salih Misaibih, the ministry's public relations director-general, told the paper.
Security forces were on high alert in Riyadh with increased patrols and tighter control of all vehicles entering the sprawling diplomatic quarter west of the capital, added Arab News.
The authorities had received 2000 calls about the car, eight of which were detailed sightings, the daily said, after the ministry announced on Friday it had "confirmed information that a vehicle registered in the name of one of the suspects has been equipped with a big quantity of explosives to be used in a criminal act."
The vehicle was a burgundy 1991 GMC Suburban with the licence plate number 034 and was "last seen in the Al-Rabwa neighbourhood, east of the capital," a statement said.
The rear windows have been covered and a curtain separates the driver and front passenger seats. All the back seats had also been removed.
The interior ministry urged the capital's residents to be on the
alert, "especially since this misled group (of terror suspects)
tends to hide these dangerous components in residential areas."
Foiling the attempt
Arab News said the seven million riyal reward was for "actions that foil an attempted terrorist attack" and followed separate offers of one million riyals for information leading to the arrest of one of the men on a wanted list and five million riyals for information leading to the arrest of more than one of the wanted suspects.
"Any person who provides information leading to the capture of the vehicle will, in line with a royal decree, receive a reward of seven million riyals."
Saud bin Salih Misaibih, Interior Ministry public relations director-general
The interior ministry released in early December a list - which included 23 Saudis, two Moroccans and a Yemeni - wanted for alleged links to two suicide bombings on residential compounds in Riyadh in November and May that killed 52 people.
The list was subsequently narrowed to 24 after one of the wanted suspects was killed in a clash with security forces and another surrendered to authorities. The body of another suspect on the list was found in a desert area north of the capital.