An oil tanker under US sanctions for allegedly transporting Iranian petroleum products has become the latest victim of resurgent Somali piracy when it was boarded off the coast of Yemen and diverted toward Somalia.
The Eritrea-flagged Sibu 1 was seized on Thursday by six armed individuals, according to the United Kingdom Maritime Trade Operations (UKMTO).
The tanker was sanctioned last December by the US Treasury for allegedly being part of a "shadow fleet" that helps Iranian petroleum products evade US sanctions.
The Sibu 1 was at least the 13th vessel attacked this year off the coast of Somalia or in the Gulf of Aden that links Somalia and Yemen, according to data from the International Maritime Bureau and reports by UKMTO.
There were only five such attacks in all of 2025, according to the IMB data. Hundreds of attacks by Somali pirates from 2008 to 2014 created a security crisis in the western Indian Ocean that cost the global economy billions of dollars, including hundreds of millions of dollars in ransoms.
A coordinated international security response largely ended those attacks and a spate of hijackings in 2023 and 2024 also died down following a robust naval response.
But experts say the failure to address the root causes of piracy linked to poor economic and security conditions in Somalia mean it can always re-emerge.
"The piracy was always suppressed. It was never really fully eradicated," said Timothy Walker, a senior researcher at the Institute for Security Studies in Pretoria.
Experts have pointed to impacts of the Iran war on the piracy surge, including elevated oil prices that make tankers more attractive targets and the diversion of naval assets previously focused on piracy to the Strait of Hormuz and Red Sea to deal with threats from Iran and its Houthi allies in Yemen.
Some have cited evidence of collaboration between the Houthis and Somali pirates after several vessels were seized near the Yemeni coast.
Jay Bahadur, a researcher and co-director of the Scopus Insights consultancy, said the seizure of an Iran-linked vessel like Sibu 1 made him very sceptical of Houthi links to the recent hijackings but added it was clear Somali pirates were receiving support from Yemeni nationals, including arms trafficking networks.
"You're having these traditional, longstanding relationships built around arms trafficking and human smuggling built up between Yemeni criminal actors and Somali criminal actors," he said.
(Additional reporting by Natalia Chumakova Editing by Gareth Jones)