A large blast went off Wednesday in the Saudi capital Riyadh, a senior Interior Ministry official said.
The official said authorities were tipped off to six explosives planted in the city, and were able to find and defuse five.
However, he said the sixth exploded before police could disarm it.
The blast went off on Al-Washim street in the Naseriah neighborhood. The area is near the Saudi Information Ministry.
A police station is also located on the same street.
There were no immediate reports of deaths or injuries.
Truck bombs defused
On Tuesday, Saudi security forces defused two truck bombs outside Riyadh, a security source said, bringing the number of car bombs seized in the kingdom to five within a week.
The vehicles were discovered late Monday at Shuaib Juraidal in Rumhiyah village, 56 miles (90 kilometers) east of Riyadh.
After the two vehicles were found, security forces and helicopters searched the area for armed men, who fled the area in a Jeep, residents told Arab News.
On Sunday, an Interior Ministry official announced the arrest of eight suspects linked to recent deadly clashes with security forces and car bombs.
The Saudi Press Agency quoted the official giving details of three seized vehicles packed with thousands of pounds of explosives, including one vehicle authorities had been searching for since February.
Saudi police set up several checkpoints in Riyadh.