Saudi Arabia has said two Saudi nationals carried out last month's suicide attack in the capital, Riyadh, killing 18 people and injuring 120.
Up to five buildings were demolished in the blast
A statement by the Saudi Interior Ministry said two of the attackers had been identified by DNA tests.
They were named as Ali bin Hamed al-Maabadi al-Harbi and Nasser bin Abdullah bin Nasser al-Sayyari.
The statement - read on state television - said both men were wanted by authorities on security charges.
The ministry said the security forces had discovered who was behind this operation and were still pursuing them.
The statement did not mention al-Qaeda, which Saudi authorities had blamed for the attack.
It was the first detailed official account of the 9 November bombing in the Muhaya residential compound that housed mainly Arab foreign workers.
Most of the victims were non-Saudi Arabs
Al-Harbi and al-Sayyari's accomplices drove to the compound gate in a car and started throwing hand grenades and shooting at the guards, the statement said.
Then the two men themselves entered the compound in a different car - a Toyota jeep disguised as a police vehicle and loaded with 300 kilogrammes of explosives.
"It was detonated in a suicide operation inside the compound," the statement said.
It said the attackers planned the operation at a private house in Riyadh, where equipment used to paint cars had been found.
More than 50 people - including bombers - were killed in two suicide bomb attacks in the kingdom in the last six months.
Under growing pressure from the United States, the Saudi authorities have been clamping down heavily on suspected militants since the first attacks on western compounds in Riyadh last May.
Last week, Saudi officials said they had foiled a bomb attack when they discovered a car packed with more than a tonne of explosives.
As the discovery was made on 25 November, two suspected militants died in a shoot-out with police.
The authorities said the attack was timed for the start of the three-day Eid al-Fitr holiday, marking the end of the Muslim holy month of Ramadan.