A US-sanctioned tanker linked to China is transiting the Strait of Hormuz in what amounts to the first major test of President Trump’s naval blockade, which took effect on Monday.

The Rich Starry, a medium-range tanker formerly known as Full Star, was blacklisted by Washington in 2023 for helping Iran evade energy sanctions. The vessel’s current transit is its second attempt in under 24 hours — it initially turned back near Iran’s Qeshm Island just as the blockade came into effect, before restarting hours later while broadcasting that it has a Chinese owner and crew.

It remains unclear whether the tanker visited Iranian ports before transiting or what cargo it carries. The vessel is registered under a Malawi flag, though the landlocked African nation has said it maintains no official registry for ocean-going ships. Maritime database Equasis links the ship’s owner, Full Star Shipping Ltd, to the sanctioned Shanghai Xuanrun Shipping Company.

A second tanker, the Elpis, also entered the Gulf of Oman via Hormuz as the blockade began. Ship-tracking platforms Kpler and Vortexa indicate the Elpis had docked at an Iranian port before attempting transit.

No vessels with active transponders have been seen sailing into the Persian Gulf since the blockade took effect, according to tracking data. Most shipping operators contacted across the Middle East and Asia said they would pause movements until the enforcement details of the blockade — intended to restrict Iran’s capacity to sell oil — became clear.

China’s Foreign Minister Wang Yi has urged global stakeholders to pursue peace talks between Tehran and Washington. The incident underscores the geopolitical tensions surrounding Hormuz that continue to push oil prices above $100 per barrel.