China's Foreign Ministry called the U.S. blockade of Iranian ports in the Strait of Hormuz a "dangerous and irresponsible act" on Monday, CNBC reported. The statement came as the Islamabad talks between Vice President Vance and Iranian negotiators broke down over the weekend, with the U.S. pivoting from diplomacy to maritime pressure.

Beijing's response was measured in tone but pointed in substance. China is the largest buyer of Iranian crude oil and has a direct commercial interest in the strait reopening. The blockade does not merely pressure Tehran. It disrupts Chinese energy supply at a moment when Beijing is trying to maintain economic stability.

The Blockade Begins

The U.S. Navy began preventing ships from entering and exiting Iranian ports on Monday after talks collapsed, according to CNBC. More than 10,000 troops and roughly a dozen naval vessels are enforcing the interdiction. Trump posted on Truth Social over the weekend that the Navy would blockade "any and all Ships trying to enter, or leave" Iranian ports via the strait.

The operational scope is significant. Central Command reported that American forces have already directed multiple vessels to turn around or return to port. The enforcement extends to Iranian-flagged vessels, ships carrying Iranian cargo, and any vessel bound for an Iranian port regardless of flag state.

China's Exposure

China imported an estimated 1.5 million barrels per day of Iranian crude before the war, much of it through sanctions-evasion channels. Beijing has maintained neutrality throughout the conflict, abstaining from every UN Security Council vote. That neutrality becomes harder to sustain when American warships are intercepting Chinese-linked commercial traffic.

Trump told reporters Monday that he was "very disappointed with NATO" for not assisting with the blockade, but also suggested that allies would come around. The BBC reported that the United Kingdom declined to participate, according to NBC News.

The blockade is leverage against Iran. It is also a test of how far the United States can stretch maritime enforcement before drawing other major powers into a confrontation that has, until now, been bilateral.