RIYADH/WASHINGTON — Saudi Arabia is expected to restore Monday at least a third of the production lost to weekend attacks on two major oil facilities, according to experts and reports, as President Donald Trump warned that the US was "locked and loaded" to respond to attacks on Saudi oil infrastructure that Washington blamed on Iran.

It is the first time the president has hinted at a potential American military response to the drone attacks, which slashed Saudi oil production by half and led both the Kingdom and the United States to announce they may tap their strategic reserves.

"Saudi Arabia oil supply was attacked. There is reason to believe that we know the culprit, are locked and loaded depending on verification, but are waiting to hear from the Kingdom as to who they believe was the cause of this attack, and under what terms we would proceed!" Trump tweeted.

Energy Minister Prince Abdulaziz Bin Salman said Sunday the Kingdom would use its vast inventories to partially compensate for the lost production, and the US also authorized the release of its reserves.

Prince Abdulaziz inspected the Aramco facilities in Abqaiq Sunday. He was accompanied by Prince Ahmed Bin Fahd Bin Salman, deputy governor of the Eastern Region, according to Saudi Press Agency (SPA).

The minister also held a meeting with the Chairman of Saudi Aramco’s board of directors Yasser Al-Rumayyan, the company’s President and Chief Executive Eng. Amin Nasser and a number of officials.

A report by Al-Arabiya television said Monday, however, that Aramco was ready to restart the Khurais plant, which handles 1.5 million bpd. Saudi Arabia pumps 9.9 million bpd, almost 10 percent of global demand, of which seven million bpd is destined for export.

The United States is also considering increasing its intelligence sharing with Saudi Arabia after Saturday's attack, which halved the Kingdom's production and jolted world oil markets, US officials told Reuters.

The US officials, who spoke on condition of anonymity, did not say how broad any increase in intelligence sharing might be or discuss other options being weighed by the administration as a response to the attack on the world's biggest crude oil processing plant.

For, months Iranian officials have issued veiled threats, saying that if Tehran is blocked from exporting oil, other countries will not be able to do so either. However, Iran has denied any role in a series of attacks in recent months, including bombings of Tankers in the Gulf and the strikes claimed by the Houthis.

On Sunday, one US official said: "There's no doubt that Iran is responsible for this. No matter how you slice it, there's no escaping it. There's no other candidate."

Britain on Monday said an attack on Saudi Arabia's oil facilities was serious and outrageous. The attack “was a wanton violation of international law,” British Foreign Secretary Dominic Raab said, adding that the United Kingdom stood firmly behind Saudi Arabia.

“This was a very serious attack on Saudi Arabia and the oil installations and it has implications for global oil markets and supply,” Raab said. “It's a very serious, an outrageous act, and we need to have a clear and as united as possible international response to it.”

Russia , meanwhile, urged countries in the Middle East and outside the region not to draw "hasty conclusions" on who staged the attacks on Saudi oil facilities.

Kremlin spokesman Dmitry Peskov, asked about the US statement, said: "We have a negative attitude towards rising tensions in the region and call for all countries in the region and outside of it to avoid any hasty steps or conclusions which may deepen destabilization."

China on Monday too urged the United States and Iran to "exercise restraint" after a drone attack on Saudi oil infrastructure, which Washington has blamed on Tehran. Chinese Foreign Ministry spokeswoman Hua Chunying also said it was not responsible to accuse others "in the absence of a conclusive investigation or verdict".

"The Chinese side's position is that we oppose all actions that enlarge or intensify conflict," she told reporters at a regular press briefing in Beijing. "We hope that both sides can exercise restraint and jointly safeguard the peace and stability of the Middle East," she added.

The Organization of the Petroleum Exporting Countries' (OPEC) Secretary General Mohammad Sanusi Barkindo said on Monday that Saudi Arabia and Aramco have risen to the challenge, and the manner in which they handled the attacks on oil facilities is commendable.

"Saudi authorities and Aramco have risen to the challenge, and the way and manner in which they have handled this development is commendable," Barkindo told Bloomberg in a phone interview.

"They have been in touch with us as well as other countries, so by and large the situation is under control," he added. He stated that Saudi Arabia was transparent about the issue, and that there will be no emergency OPEC meeting.

"The Kingdom is strong and firm in ensuring that all their customers remain supplied," Barkindo said. — Agencies