NATO chief Jens Stoltenberg said Monday he was "extremely concerned" about escalating tensions following strikes on Saudi oil facilities at the weekend, accusing Iran of "destabilising" the region.
Stoltenberg's comments in an interview with AFP in Baghdad were his first on the strikes on two major Saudi oil facilities that were claimed by Yemen's Huthi rebels but which both Washington and Riyadh have blamed on Tehran.
The weekend strikes on Abqaiq - the world's largest oil processing facility - and the Khurais oil field in eastern Saudi Arabia have roiled global energy markets with prices spiking Monday to record highs.
Yemen's Iran-aligned Huthi rebels claimed responsibility for the strikes but Washington has squarely blamed Iran, with President Donald Trump saying the US is "locked and loaded" to respond.
Saudi's energy infrastructure has been hit before, but this strike was of a different order, abruptly halting 5.7 million barrels per day (bpd) or about six per cent of the world's oil supply.
The Saudi-led coalition, which is bogged down in a five-year war in neighbouring Yemen, reiterated the assessment that the Huthis were not behind it, pointing the finger at Iran for providing the weapons.
Russia urged "all countries to avoid hasty steps or conclusions that could exacerbate the situation" while the European Union stressed all sides should show "maximum restraint".
The weekend strikes on Abqaiq and the Khurais oil field in eastern Saudi Arabia have roiled global energy markets with prices spiking Monday to record highs.