Saudi Arabia's King Abdullah ordered all necessary measures to protect the kingdom against potential "terrorist threats", state news agency SPA reported on Thursday.

The agency said the monarch gave the order after chairing a meeting of the world's top oil exporter's national security council to discuss fallout from developments in neighbouring Iraq.

"Concerned for the national security of the kingdom of Saudi Arabia against any measures that terrorist organisations or any other groups might resort to, that could destabilise security of the homeland, he (the king) has ordered all necessary measures to protect the gains of the homeland and its stability, and the security of the Saudi people," SPA said.

The militant Islamic State in Iraq and the Levant (ISIL) has spearheaded a lightning advance through Iraq and - aided by other Sunni Muslim militants, tribal leaders and remnants of Saddam Hussein's Baath Party - seized large swathes of the country this month.

The advance has rattled wealthy Gulf states, especially Saudi Arabia, which had faced a wave of attacks by al Qaeda militants between 2003 and 2005 that killed scores of people, including many foreigners and security forces.-Reuters