The gunman suspected of killing an American in Saudi Arabia's capital had no known links to "extremist" organisations, the interior ministry said, as Washington sought clarification about the killer's motive.
Abdulaziz Fahad Abdulaziz Alrashid, 24, the alleged shooter who authorities say was wounded in a gunfight with security forces, is a US-born Saudi who had been fired from US defence contractor Vinnell Arabia, an interior ministry spokesman said in a statement late Tuesday.
The dead American and another US national who was wounded also worked for Vinnell Arabia, which trains the Saudi Arabian National Guard, the spokesman said.
"The security services have no proof that (the killer) had prior links with extremist organisations," he said in a statement carried by the official Saudi Press Agency.
An investigation into the motive for the shooting is continuing, he added.
The attack occurred Tuesday at a petrol station in eastern Riyadh.
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US Secretary of State John Kerry told reporters in Paris that Washington is "in close contact" with the Saudi government, and "evaluating our security posture," following the shooting.
"We're continuing to gather details about the incident," Kerry told a news conference.
"I can't speak to the motive at this point, except to say to you that there are some questions about whether it was or wasn't a disgruntled employee," he said.
Riyadh's embassy in Washington said in a statement that the suspect was recently dismissed from his job "due to drug related issues".
Tuesday's shooting was the first deadly attack on Westerners in Saudi Arabia since several were killed in a spate of Al-Qaeda violence between 2003 and 2006.
It came as the ultra-conservative Sunni-majority kingdom participates in a US-led campaign of air strikes against jihadists of the Islamic State group in Syria.