The head of Saudi Aramco hit out Wednesday at the lack of global resolve to stop attacks on more oil installations, one month after strikes on two of its facilities.

The September 14 attacks on Aramco plants in Abqaiq and Khurais -- which initially halved the kingdom's crude output and sent global energy markets into a tailspin -- intensified geopolitical tensions in the crude-rich Middle East.

"An absence of international resolve to take concrete action may embolden the attackers and indeed put the world's energy security at greater risk," said Aramco CEO Amin Nasser, speaking at the Oil & Money industry conference in London.

The strikes on Abqaiq -- the world's largest oil processing facility -- and the Khurais oil field in eastern Saudi Arabia roiled oil markets and revived fears of a conflict in the tinderbox Gulf region.

Aramco dethroned Apple as the world's most profitable firm last year
Aramco dethroned Apple as the world's most profitable firm last year AFP / Fayez Nureldine

Observers say the attacks have also exposed the vulnerabilities of Saudi oil infrastructure, while the extent of the damage at the plants remains unclear.

Washington has concluded that the strikes were launched from Iranian soil and that cruise missiles were used. Tehran denies its involvement.

The attacks were claimed by Yemen's Huthi rebels. Saudi leads a military coalition against the Iran-backed Huthis, which have carried out dozens of cross-border drone and missile attacks on Saudi targets, including oil facilities.

World oil prices briefly soared following strikes which temporarily knocked offline six percent of global oil production.