Saudi Arabia's King Salman bin Abdelaziz said on Tuesday that the kingdom was able to handle the Saturday's "cowardly attacks" which resulted in major fires at two oil facilities operated by Saudi state oil giant Aramco.

The "kingdom will defend its lands and vital facilities, and is able to respond to such acts whatever their sources are," he told the cabinet.

The attacks significantly disrupted Saudi oil production, triggering a global oil supply slump of more than 5%.

Oil prices surged as soon as markets opened on Monday, with the US, Russia and even Japan saying they were considering tapping into oil reserves.

Collective response

Chancellor Angela Merkel and British Prime Minister Boris Johnson discussed the attacks over the telephone on Tuesday, agreeing on "the need to work together, alongside international partners, to agree a collective response," according to a Downing Street statement.

Saudi invites UN to investigate

Sources cited by the Reuters news agency said a return to normal production could take months following the attacks, which were claimed by Houthi rebel fighters in Yemen who are backed by Iran.

Saudi Arabia has invited the UN and international experts to "view the situation on the ground and to participate in the investigations."

Read more: Iran-US tensions flare in the Persian Gulf: What's at stake?

Aramco has been preparing for an initial public offering (IPO) stock market launch, even naming a new chairman and mandating nine banks in top roles. The company said it was still pushing ahead with the IPO plans, perhaps realizing them as early as November.

Iran rejects US talks after Saudi oil attack blame

Iranian supreme leader Ayatollah Ali Khamenei on Tuesday rejected possible negotiations with the US after the White House suggested Iran was involved in attacks on key Saudi oil facilities.

"The policy of 'maximum pressure' against the Iranian nation is worthless and all Islamic Republic of Iran officials unanimously believe there will be no negotiations with the US at any level," Khamenei said, referring to the US' latest strategy on Iran.

Earlier this month, US officials raised the prospect of direct talks between US President Donald Trump and his Iranian counterpart Hassan Rouhani on the sidelines of the UN General Assembly scheduled for next week.

Secretary of State Mike Pompeo and Treasury Secretary Steven Mnuchin said there would be "no preconditions" for the talks, but Trump later dismissed the remark as an "incorrect statement."

Read more: German government split on Saudi arms ban

US 'ready' to defend interests

US Secretary of State Mike Pompeo was heading to Saudi Arabia on Tuesday, according to US Vice President Mike Pence. Washington was evaluating evidence on the attacks and stands ready to defend its interests and allies in the Middle East, Pence said.

Washington and Tehran have seen relations deteriorate since Trump unilaterally withdrew the US from the Iran nuclear deal. The White House has also deployed warships and bombers to the Persian Gulf after several oil tankers were sabotaged over the summer.

Rising tensions

In the latest development between the rivals, the White House on Monday suggested that Iran was behind attacks against oil facilities in Saudi Arabia although Houthi rebels in Yemen had claimed responsibility.

"I'm not looking to get into new conflict, but sometimes you have to," Trump said. "That was a very large attack, and it could be met by an attack many, many times larger."

"Certainly, it would look to most like it was Iran," he added.

Germany, the UK and China have urged caution, saying efforts must be taken to verify who is responsible for the attack before attributing blame.

Read more: Saudi Arabia vs. Iran: From 'twin pillars' to proxy wars

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kw,ls/msh (AFP, AP)