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 a role in specific attacks, including bombings of tankers in the Gulf and previous strikes claimed by the Houthis.
Foreign Ministry spokesman Abbas Mousavi called the U.S. accusations of Iranian involvement in Saturday’s attacks “unacceptable and entirely baseless”.
Iran said on Monday it had seized a vessel accused of smuggling diesel fuel to the United Arab Emirates. Tehran has long fought against smuggling of its subsidized fuel.
Russia and China said it was wrong to jump to conclusions about who was to blame for the attack on Saudi Arabia.
“Proposals on tough retaliatory actions, which appear to have been discussed in Washington, are even more unacceptable,” Russia’s Foreign Ministry said in a statement.
Britain – Washington’s close ally but wary of its hardline Iran policy – stopped short of ascribing blame but described the assault as a “wanton violation of international law”.
Washington has imposed its “maximum pressure” strategy on Iran since last year when Trump pulled out of an international deal that gave Tehran access to world trade in return for curbs on its nuclear program.
U.S. allies in Europe oppose Trump’s strategy, arguing that it provides no clear mechanism to defuse tensions, creating a risk that the foes could stumble into war.
Trump has said his goal is to force Iran to negotiate a tougher agreement and has left open the possibility of talks with President Hassan Rouhani at an upcoming U.N. meeting. Iran says there can be no talks until Washington lifts sanctions. Its foreign ministry said on Monday Rouhani would not meet Trump.
Officials in big energy-exporting countries were eager to assert that global markets could cope with the Saudi outage.
“We have spare capacity. There are volumes we can deal with as an instant reaction,” the energy minister of the United Arab Emirates, Suhail al-Mazrouei, told reporters in Abu Dhabi.
Russian Energy Minister Alexander Novak told reporters there was enough oil in commercial stockpiles to cover the shortfall.
The giant Saudi plant that was struck cleans crude oil of impurities, a necessary step before it can be exported and fed into refineries. The attack cut Saudi output by 5.7 million barrels a day, or around half.
Saudi Arabia is not only the world’s biggest oil exporter, it has a unique role in the market as the only country with enough spare capacity to increase or decrease its output by millions of barrels per day, keeping the market stable.
Big countries such as the United States and China have reserves designed to handle even a major outage over the short term. But a long outage would make markets subject to swings that could potentially destabilize the global economy.