Iran and US escalate threats ahead of Monday deadline in widening conflict

Monday at 8:13 p.m. Brasília time, Donald Trump's ultimatum to Iran expires. The demand is simple in its stakes: reopen the Strait of Hormuz, the waterway through which one-fifth of the world's oil and liquefied natural gas flows, or face American bombardment of Persian energy infrastructure. By Sunday, both sides had abandoned any pretense of restraint, trading threats that promised to reshape global markets and regional stability in the hours ahead.

The conflict itself is only three weeks old, but the rhetoric has already calcified into something harder and more dangerous. Iranian President Masoud Pezeshkian took to social media to declare that threats and terror only strengthened national unity, insisting the strait remained open to all except those who violated Iranian soil. The message was defiant but measured. Others in Tehran's power structure were less restrained. Mohammad Ghalibaf, the influential speaker of parliament, announced that if American strikes came, Iran would destroy critical energy infrastructure and oil facilities in ways that could not be reversed, driving commodity prices upward for years. He then pivoted to threats against international banks holding American Treasury bonds—institutions he described as soaked in Iranian blood. The rhetorical flourish stumbled on a practical reality: China, Iran's closest ally, holds roughly $700 billion in American Treasury securities, making Ghalibaf's threat more theatrical than executable.

The Revolutionary Guard Corps issued its own warnings with sharper teeth. They promised to close the Hormuz Strait entirely if Iran's energy systems came under attack, and to target every company with American operations in the Persian Gulf. An unnamed military spokesman extended the threat to desalination plants—infrastructure so vital to the arid nations of the region that damage would ripple far beyond Iran's borders. These were not idle warnings. Iranian drones and short-range missiles had already proven their reach and accuracy; the vulnerability of regional infrastructure to such weapons was no secret to anyone paying attention.

Trump's ultimatum itself represented a departure from his usual approach to international confrontation. His threats typically carried the weight of theater rather than consequence. But this time, American forces were already in motion. Treasury Secretary Scott Bessent, when asked Sunday whether the president's Friday suggestion that he might slow the campaign contradicted the Monday deadline, offered a phrase that captured the administration's logic: sometimes you need to escalate to de-escalate. Bessent then hinted at something more concrete—a possible ground operation against Kharg Island, the hub through which Iran exports 90 percent of its oil. Roughly 5,000 Marines were heading toward the Middle East in two expeditionary groups; specialists calculated that one-fifth of that force could seize the island. What came after seizure was the harder question: positioned off Iran's coast, Kharg would remain exposed to relentless bombardment.

The economic dimensions of the standoff had already begun to reshape global markets. Oil prices had climbed to nearly $120 per barrel the previous week. Natural gas had spiked further when Israel struck Iran's portion of the world's largest gas field, prompting Tehran to destroy almost 20 percent of Qatar's processing capacity. Bessent defended one of the war's most controversial decisions—authorizing the sale of sanctioned Iranian oil to ease barrel prices—by framing it as temporary, a necessary measure to prevent economic catastrophe. The irony of effectively financing an adversary seemed to trouble him less than the alternative.

The Strait of Hormuz itself remained technically navigable, though barely. Iran had allowed some vessels through a route in its territorial waters, raising suspicions that the main shipping lanes—three kilometers wide in each direction—might be mined. In practice, commerce had ground to a halt. A tanker near the United Arab Emirates coast caught fire on Sunday, a reminder that even without formal closure, the waterway had become a zone of active danger. Iran's leadership maintained the fiction that the strait was open to neutral nations like India and friendly ones like China, but the reality on the water told a different story.

As Sunday turned toward Monday, the violence continued unabated. Israeli and American aircraft maintained their bombing campaigns. Iranian missiles and drones kept launching toward Israeli and American-aligned targets. The ultimatum's expiration would not pause this machinery; it would likely accelerate it. Markets braced for Monday's opening. Analysts calculated the cost of disrupted oil supplies, blocked shipping lanes, and potential strikes on infrastructure that underpinned the region's fragile prosperity. The deadline was not a moment of decision but a threshold being crossed—the point at which threats became actions, and the conflict entered a new and more volatile phase.