Trump said in a social media post Saturday evening that he would “hit and obliterate” Iran’s power plants, beginning with the biggest one, if it didn’t open the strait within 48 hours.

The comments from Trump, on his Truth Social media platform, marked a dramatic escalation in the US president’s rhetoric about the strait, a day after he said he was thinking about “winding down” the military operation and that the responsibility for policing Hormuz would fall to the countries reliant on shipping through the corridor.

Threats have nearly ground shipments of commodities to a halt through the Strait of Hormuz, which provides transit for roughly 20% of the world’s oil and gas. The resulting energy supply shock has sent crude prices soaring, with international benchmark Brent futures closing at $112.19 on Friday.

The declaration also comes despite Trump’s appeal for a halt in Israel’s strikes on energy assets in the region, which risk inspiring retaliatory attacks by Iran on oil and gas infrastructure and further limiting the flow of those supplies to world markets.

The region’s energy assets have increasingly come into focus as attacks widen, with Israel striking the South Pars gas field last Wednesday, and Iran retaliating with its own volleys on the world’s largest LNG facility, in Qatar.

More than 100 people were injured in Israel on Saturday by multiple Iranian strikes in the country’s south, as Tehran sought to retaliate for an earlier attack on its own nuclear facility. 

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As the conflict, entering its fourth week, caused a surge in energy prices, the US Treasury has taken the extraordinary step of allowing the sale of Iranian oil and petrochemical products that had already been loaded onto tankers despite existing sanctions.

The price spikes pose political risks for Trump at home, just eight months before midterm elections expected to hinge largely on voters’ view of the US economy and consumer costs.

Although the US is pumping record amounts of oil and gas domestically, and is less reliant on Middle East resources than China, Japan and other nations, the supply shock tied to the strait is being felt in higher prices globally.

Trump’s mixed signals have left governments and markets scrambling to keep up with the shifting messages. On Friday, he posted: “We are getting very close to meeting our objectives as we consider winding down our great Military efforts in the Middle East.”

But Israeli Defense Minister Israel Katz said Saturday that the joint campaign would intensify significantly, a day after Tehran launched ballistic missiles at the joint US-UK military base in Diego Garcia — nearly 2,500 miles (4,000 kilometers) away from Iran. 

The base suffered no damage, according to a person familiar with the matter speaking on condition of anonymity, but the attack demonstrated a capability that goes beyond what Iran was known to have possessed. 

Trump’s efforts to enlist US allies in helping reopen the strait to widespread commercial ship traffic have largely been rebuffed. Trump, in turn, has lashed out at fellow NATO members, branding them “cowards” for not joining the efforts.

Trump previously has promised US naval escorts and a government-backed reinsurance program to help lower the barriers to sending ships through the strait amid the conflict. However, there are no signs that any tanker has yet transited with the help of the US Navy.

Israel and Iran also traded more missiles strikes on Saturday.

Iran said it fired missiles at the Israeli city of Dimona, which also lends its name to a nearby nuclear research facility, in what Iranian state TV labeled a response to an earlier attack on the country’s Natanz nuclear facility. 

Israeli authorities said some 47 people were injured. A second strike landed in southern Israel, where three residential buildings suffered significant damage in Arad and hospital officials said more than 60 people were wounded, including seven who were taken to the hospital.