Saudi security forces have killed a gunman who had fired upon the palace of Saudi interior minister Prince Nayef bin Abdul Aziz Al Saud in Jeddah.

"At 1 a.m. on Saturday, a person carrying a gun fired at a checkpoint in Abdulrahman Al-Malki Street in Jeddah. He was dealt with swiftly and was killed," said a statement by the Saudi Press Agency (SANA).

"The event is still under investigation," the statement by SANA added.

However, a government source told Agence France Presse (AFP) that two men were involved in the shooting and that the second man had been arrested.

"Two men opened fire after midnight on the… residence of Prince Nayef [and] the security forces retaliated, killing one of them," the source told AFP.

The source identified the gunman as being part of the Zahrani family and that he was apparently "under the influence of drugs.” He suggested that the incident was purely done on an individual basis and did not have any connection to any organized aggression against the government.

Prince Nayef is third in line to the Saudi throne and conducted the state’s crackdown against al-Qaeda terrorists between 2003 and 2006.

According to Al Jazeera, two years ago the son of the interior minister, Prince Mohammed bin Nayef Al Saud, who is in charge of Saudi Arabia’s counter-terrorism program, survived a murder attempt by a suicide bomber.