Saudi security forces killed a gunman early on Saturday after he fired at a checkpoint near the Interior Minister's palace in Jeddah, the state news agency said.
Police said they were unable to confirm whether the incident was militant-related.
"At 1 a.m. on Saturday (2200 GMT Friday), a person carrying a gun fired at a checkpoint in Abdulrahman Al-Malki Street in Jeddah. He was dealt with swiftly and was killed. The event is still under investigation," the SPA statement said.
There were no other deaths or casualties, it said.
About two years ago, the interior minister's son, Prince Mohammed bin Nayef, who oversees the Saudi counter-terrorism program, was the target of a failed suicide bombing by a man posing as a repentant militant.
Interior Ministry spokesman Mansour al-Turki referred a call for comment to Jeddah police spokesman Mesfer Aljoayed, who was not immediately available.
Police First Lieutenant Nawaf Nasser said he could not confirm the incident was a militant attack. "There is an investigation on-going. It is not complete yet and there will be a final statement once it is," he said.
The world's No. 1 oil exporter, Saudi Arabia, is an absolute monarchy without an elected parliament or political parties.
Interior Minister Prince Nayef bin Abdul-Aziz, who is believed to be in his late 70s, spearheaded a crackdown in 2003-06 on al-Qaeda militants who aimed to destabilize the country through a campaign of attacks.
"Nayef and his sons are a primary target for Qaeda and the cells, as you saw with the attack on his son," said Riad Kahwaji, chief executive of ENIGMA think tank in Dubai.
"It will come as no surprise if it turns out (Saturday's)attack was by one of the Qaeda cells. It shows determination and some capacity, also their intent to keep the Saudi officialdom on its toes," he said.
Saudi Arabia, a close U.S. ally, has grown increasingly concerned that months of political turmoil in neighboring Yemen have strengthened al Qaeda's Yemen-based regional wing, Al Qaeda in the Arabian Peninsula (AQAP).
AQAP last month issued a message from its military commander threatening to attack Saudi Arabia and its ruling family.