US special operations on ship from China to Iran US Navy.

The United States has seized cargo from a ship sailing from China to Iran in the Indian Ocean. The incident took place last month. A US official said that a US special operations team boarded the ship and seized the goods, which were aimed at preventing Tehran from rebuilding its military capabilities.

The Wall Street Journal first reported the information on Friday (December 12). The seizure comes amid a long-standing standoff between the US and Iran over their nuclear programs.

Iran was embroiled in a brief war with Israel and the US this summer. More than 1,000 people were killed in the 12-day long-range missile and airstrike conflict. In that conflict, US stealth bombers attacked Iranian nuclear facilities. US officials claim that this caused “severe damage” to Iran’s nuclear weapons program. But regional officials and analysts fear a new conflict could be inevitable.

The US official said the US had been monitoring the ship's movements as it sailed from China to Iran, speaking on condition of anonymity because he was not authorized to speak publicly. The ship was several hundred miles off the coast of Sri Lanka when US special forces launched the operation. Commandos boarded the ship, seized its cargo and then allowed it to continue its journey.

It was not clear what kind of goods were on board. However, the official said the cargo contained "dual-use" materials that could be used for civilian purposes as well as for conventional weapons. The operation came weeks before the recent seizure of an oil tanker off the coast of Venezuela.

A spokesman for the US Indo-Pacific Command, which oversees military operations in the region, declined to comment.

The New York Times reports that Iranian factories are working around the clock to build up a stockpile of long-range missiles and drones that could be used to strike Israel. Iran tried to overwhelm Israel’s air defenses with a large number of weapons in the recent 12-day conflict and will likely try to import as many new weapons components as possible before another conflict.

The United States is increasingly trying to control the supply of dual-use goods, especially guided weapon systems, microelectronics and software needed to build long-range drones. These components are difficult to explicitly ban or impose sanctions on because they have civilian uses.