On the 12th (local time), a ship is sailing in the Strait of Hormuz off the coast of the Musandam Governorate in Oman. Reuters Yonhap News

The United States began a maritime blockade against Iran centered on the Strait of Hormuz at 10 a.m. Eastern on the 13th (11 p.m. Korea time on the 13th).

This is seen as a high-stakes move by U.S. President Donald Trump after the first talks to end the war between the United States and Iran collapsed. The aim is to cut off revenue for Iran by blocking tankers exporting Iranian crude, countering Iran, which has maintained a de facto blockade by controlling the strait even after the two-week truce agreed on the 7th.

However, Iran has also signaled a hardline confrontation, raising tensions around the Strait of Hormuz. In the worst case, there are concerns that Iran could respond to the U.S. blockade with military attacks, the truce scheduled through the 21st could collapse, and the war could escalate.

Earlier, President Trump said the previous day on the Truth Social platform that he would immediately begin procedures to blockade all vessels transiting the Strait of Hormuz. The U.S. Central Command, which oversees the Middle East, set 10 a.m. on the 13th as the time to implement the blockade of all maritime traffic entering or leaving Iranian ports.

In a notice sent to merchant mariners, Central Command also warned that all vessels entering or departing the blockade zone without U.S. military authorization would be intercepted, turned back, or seized. However, it stated that ships arriving from or departing to locations other than Iran would be allowed to pass through the Strait of Hormuz without interference.