Natasha Kaneva, a commodities analyst at JPMorgan bank, said in an analysis on Monday that at least four ships had been tracked exiting the strait via the Larak-Qeshm Channel, near the Iranian coast, over the previous two days.

“This is not a standard route for vessels and could reflect a process designed to confirm vessel ownership and cargo, enabling passage for ships that are not affiliated to the US or its allies,” she said in a note sent to AFP.

The vessels included bulk carriers and one oil tanker, the Pakistani-flagged Karachi.

Tracking site MarineTraffic said the Karachi transited the strait with its automatic transponder system activated, where most vessels keep it turned off to avoid being targeted.