A US-sanctioned oil tanker that was hijacked last week by suspected pirates off the coast of Yemen and diverted toward Somalia is not registered in Eritrea despite flying the country’s flag, Eritrea’s government says.

The Sibu 1, which the US Treasury sanctioned last December for allegedly being part of a shadow fleet that helps Iranian petroleum products evade US sanctions, has no affiliation with Eritrea, Information Minister Yemane Gebremeskel tells Reuters.

The ship is widely listed by ship-tracking websites as sailing under an Eritrean flag, but a database run by the United Nations’ International Maritime Organization states its current flag status as “Eritrea False,” suggesting its registration is not recognized as valid.