Saudi Arabia said armed drones struck two oil pumping stations in the kingdom on Tuesday in what it called a "cowardly" act of terrorism two days after Saudi oil tankers were sabotaged off the coast of the United Arab Emirates.
The attacks took place against a backdrop of U.S.-Iranian tension following Washington's decision this month to try to cut Iran's oil exports to zero and to beef up its military presence in the Gulf in response to what it said were Iranian threats.
However, U.S. President Donald Trump denied a New York Times report that U.S. officials were discussing a military plan to send up to 120,000 troops to the Middle East to counter any attack or nuclear weapons acceleration by Iran.
"It's fake news, OK? Now, would I do that? Absolutely. But we have not planned for that. Hopefully we're not going to have to plan for that. And if we did that, we'd send a hell of a lot more troops than that," Trump told reporters.
Iran's Supreme Leader Ayatollah Ali Khamenei said there would not be war with the United States despite mounting tensions over Iranian nuclear capabilities, its missile program and its support for proxies in Yemen, Iraq, Syria and Lebanon.
"There won't be any war. The Iranian nation has chosen the path of resistance," he said in comments carried by Iran's state TV. He repeated that Tehran would not negotiate with Washington over Iran's 2015 nuclear deal with major powers.
Trump withdrew the United States from the pact a year ago and has increased economic sanctions on Iran.
Under the accord negotiated by Trump's predecessor, Barack Obama, Tehran agreed to curb its uranium enrichment capacity, a potential pathway to a nuclear bomb, in return for sanctions relief.
The Trump administration's sanctions are designed to choke off Iran's oil exports in an effort to force Iran to accept more stringent limits on its nuclear and missile programs.
U.S. national security agencies believe proxies sympathetic to or working for Iran may have sabotaged the tankers off the UAE coast rather than Iranian forces themselves, a U.S. official familiar with the latest U.S. assessments said on Tuesday.
The official said possible perpetrators might include Houthi rebels in Yemen and Iran-backed Shi'ite militias based in Iraq, but Washington had no hard evidence. On Monday, a U.S. official said Iran was a leading candidate for the tanker sabotage but the United States did not have conclusive proof.
Iran rejects the allegation of Iranian involvement and Iranian Foreign Minister Mohammad Javad Zarif said that "extremist individuals" in the U.S. government were pursuing dangerous policies.
HOUTHI TV CLAIMS DRONE ATTACK
Houthi-run Masirah TV earlier said the group had carried out drone attacks on "vital" Saudi installations in response to "continued aggression and blockade" on Yemen.
A Saudi-led coalition has been battling the Houthis for four years in Yemen to try to restore the internationally recognised government in a conflict widely seen as a Saudi-Iran proxy war.
The Houthis have repeatedly hit Saudi cities with drones and missiles, but two Saudi sources told Reuters this was the first time a facility of the state-run Aramco had been attacked by drones.
Aramco said it had temporarily shut down the East-West pipeline, known as Petroline, to evaluate its condition. The pipeline mainly transports crude from the kingdom's eastern fields to the port of Yanbu, which lies north of Bab al-Mandeb.
The energy minister of Saudi Arabia, the world's largest oil exporter, said the latest attacks caused a fire, now contained, and minor damage at one pump station, but did not disrupt oil output or exports of crude and petroleum products.
Oil prices rose on news of the attack on the Saudi pumping stations, more than 200 miles (320 km) west of the capital Riyadh. Brent was trading at $71.37 a barrel by 1715 GMT, up 1.62%.
Saudi Energy Minister Khalid al-Falih, in comments run by state media, said global oil supplies were threatened by the drone attack and Sunday's sabotage of four vessels, including two Saudi tankers, off Fujairah emirate, a major bunkering hub near the Strait of Hormuz.
A fifth of global oil consumption passes through the strait from Middle East crude producers to much of the world.
"These attacks prove again that it is important for us to face terrorist entities, including the Houthi militias in Yemen that are backed by Iran," Falih said in an English-language statement issued by his ministry.
A UAE official told Reuters the UAE was working with local and international partners from the United States, France, Norway, and Saudi Arabia to "fully investigate the incident and to identify the people or entities responsible."
The UAE has not blamed anyone for what it called sabotage on the vessels, which include a Norwegian-registered oil products tanker. France has a naval base in Abu Dhabi.
A senior European diplomat voiced skepticism that Trump's "maximum pressure" strategy would force Iran to capitulate.
"Iran is not falling to its knees," said the diplomat on condition of anonymity, saying Iran could resume its nuclear work and leave Washington with no option but military action.
"Does Trump want to go to war with Iran especially during an election campaign year?" he asked.