An attack on Saudi Arabia that triggered the biggest jump in oil prices in almost 30 years was carried out with Iranian weapons, a Saudi-led coalition said on Monday, as President Donald Trump said the United States was "locked and loaded" to hit back.
The attack on Saturday was a reciprocal measure by "Yemeni people" to assaults on their country, Iranian President Hassan Rouhani said.
Yemen's Iran-aligned Houthi group, which is battling a Saudi-led coalition in Yemen, claimed responsibility for the attacks on Saturday on sites run by state-owned Saudi Aramco.
Oil prices jumped roughly 12% on Monday after the attack sliced the kingdom's production in half and intensified concerns of retaliatory actions in the Middle East. Prices initially surged about 20%, with Brent crude posting its biggest intraday gain since the 1990-1991 Gulf crisis, before pulling back as various nations said they would tap emergency supplies to keep the world supplied with oil.
U.S. Secretary of State Mike Pompeo ruled out Yemeni involvement and accused Iran of leading the attacks.
Trump said the United States, which is embroiled in a row with Iran over its nuclear ambitions, was "locked and loaded" for a potential response.
Russia said it was unacceptable to discuss possible retaliation and said that using the incident to increase tensions around Iran was counterproductive.
An Iranian Revolutionary Guards commander said U.S. bases and aircraft carriers were within range of Iranian missiles, after Washington blamed Iran.
Israel is prepared for the possibility it might be drawn into any U.S.-Iranian confrontation over a strike on the Saudi oil plant, Prime Minister Benjamin Netanyahu said on Monday.
Sunni Muslim Saudi Arabia has previously accused Shi'ite Muslim Iran, which lies across the Gulf, of carrying out attacks on its oil facilities, charges Tehran denies. Riyadh has not blamed any party for Saturday's strikes. * Analysts said benchmark Brent, now trading at around $68 a barrel, could hit $100 if Riyadh failed to quickly bring back supply.
The Organization of the Petroleum Exporting Countries is assessing the impact but says it is too early for members to take any action on raising production or holding a meeting, the UAE energy minister and other sources said.
Saudi Aramco's full return to normal oil output volumes "may take months," two sources said on Monday.
Saudi Arabia usually ships more than 7 million bpd of oil to global destinations and has for years served as the market's supplier of last resort.Saudi Aramco has been seeking to prepare for a share sale that would make it the world's largest listed company.