Malta barred entry to a tanker containing the first oil cargo shipped by the government in eastern Libya since the country with Africa’s biggest crude reserves split into competing power centers in its east and west, Bloomberg reported.

The decision came after the National Oil Corp. (NOC) in Tripoli, in western Libya, called the shipment “illegal” and informed the country’s incipient UN-backed unity government about the eastern government’s attempt to export oil independently, an NOC spokesman, Mohamed Elharari, said by phone.

The tanker called Distya Ameya “is not authorized to enter Maltese territorial waters, and all requests will be refused,” Malta’s port authority said in an order distributed to all shipping agents in the island nation.

The ship was anchored at Hurd Bank, 12 kilometers off the Mediterranean state’s southeastern coast, according to the authority, Transport Malta, Swissinfo wrote.

Libya broke into two separately governed regions in late 2014, one centered around the capital city Tripoli in the west and an internationally recognized government in the east. Libyans are currently working with foreign support to set up a Government of National Accord. The NOC leadership in Tripoli, recognized by traders such as Glencore and Vitol Group as the country’s official crude marketer, has repeatedly warned traders against loading “illicit” cargoes of oil from the NOC administration in the east.