The accident took place in the southwestern region of Jazan, killing father, mother and two daughters while three sons suffered serious injuries.
Interior Ministry says the cluster cells were involved in several attacks and plots, including deadly suicide bombings of Shia mosques in the kingdom's Eastern Province.
The meeting brought together top members of Hamas political wing with the Saudi king, crown prince and defence minister in a possible rapprochement between the two sides.
In May, Saudi Arabia had made a cautious statement endorsing the nuclear framework agreement reached between Iran and six world powers.
"Generations of American leaders and diplomats benefited from Prince Saud's thoughtful perspective, charisma and poise, and diplomatic skill," President Barack Obama said.