The U.K. Navy issued a rare warning to mariners that higher tensions in the Middle East could impact shipping, including through the Strait of Hormuz. 

“UKMTO has been made aware of increased tensions within the region which could lead to an escalation of military activity having a direct impact on mariners,” the June 11 advisory said. “Vessels are advised to transit the Arabian Gulf, Gulf of Oman and Straits of Hormuz with caution.”

Shipping has often been risky in the Middle East, but UKMTO — which acts as a liaison between the navy and commercial shipping — rarely puts out general warnings such as this one. In May, it also issued a warning about electronic interference around Hormuz, a waterway that handles around 26% of the world’s oil trade. 

The UKMTO's alert didn’t specify the nature of the anticipated tensions.

There’s been a steady backdrop of threats to vessels over recent years. The U.S. and Iran are continuing talks about Tehran’s nuclear program, the future of which remains uncertain. Israel has also been attacking Yemen’s Houthi rebel group, which in turn has been menacing shipping in the Red Sea. Under the first Trump administration, Iran also started a campaign of hijacking vessels.