The US naval blockade on Iranian ports has entered its second day. Shipping tracking data indicates that multiple oil tankers traversing the Strait of Hormuz chose to halt or turn back after the blockade took effect. Within the first 24 hours following the official implementation of the order on Monday morning, several cargo ships departing from Iranian ports attempted to cross the narrow waterway, including at least two sanctioned tankers, but none successfully exited the mouth of the Gulf of Oman. The US military stated that no vessels passed through on the first day of implementation, and six merchant ships turned back to Iranian ports after receiving instructions. Currently, more than 15 warships, over 100 aircraft, and more than 10,000 personnel are executing the blockade mission in these waters.

Sanctioned tankers became the first test of this operation. One tanker, formerly known as the Man Xing, crossed the strait on Monday night but suddenly turned back in the Gulf of Oman on Tuesday morning, heading back toward the strait. Analysis speculates that the vessel may have turned off its positioning system while loaded with Iranian crude, or conducted a ship-to-ship transfer within the Gulf. Another sanctioned tanker, with signals indicating origin from Iran's Bushehr Port, passed through the strait on Monday afternoon before stopping at the mouth of the Gulf of Oman. Industry analysts point out that this is the first test of the blockade; Iran needs to assess the seriousness of US enforcement, and these vessels have become test subjects.

Shipping industry executives describe the current situation in the Gulf as a "double blockade." Vessels must comply with the mandatory coastal route required by the Iranian Revolutionary Guard Corps while facing interception by the US Navy in the Arabian Sea and Gulf of Oman. Iran had previously required vessels passing through the strait to pay tolls of up to $2 million and transit via approved security corridors. Within the first 24 hours after the blockade took effect on Monday, at least 11 ships entered or exited the Gulf. Tracking data suggests some appeared to be granted entry. However, a US Notice to Mariners warns that any vessel entering or exiting Iranian ports and coastal areas without authorization will face interception, diversion, or detention.

The international community has reacted strongly. The Chinese Ministry of Foreign Affairs described the US blockade as irresponsible and dangerous. Sanctions and security analysts criticize Washington for being trapped in a dilemma due to poor planning and execution: either allow Iran to continue profiting from transporting millions of barrels of oil daily through the strait, or cut off transportation but hurt Asian allies suffering from increasingly severe energy shocks. Notably, despite US insistence that the blockade is effective, shipping data platforms show that vessels, including multiple Iran-linked ships, passed through the strait after the blockade became effective. Analysts point out that vessel signals in the region are often subject to electronic jamming, which may lead to inaccurate location reports, making it difficult for the outside world to accurately assess the actual effectiveness of the blockade.