LAGOS, Nigeria—A Nigerian court has sentenced 13 Filipinos to five years in prison or a fine of one million naira ($6,800) each for stealing 12,500 metric tons of crude oil in the Niger Delta, a report said Saturday.

This Day newspaper said Justice Chukwura Nnamani of the Federal High Court in the southern city of Benin handed down the sentences Friday after the Filipinos pleaded guilty to the offense.

They were among 22 Filipinos arrested by a joint army-navy patrol on the Warri River on Nov. 14, 2008, on the vessel MT Akuada which was laden with 12,500 metric tons of crude.

The newspaper gave no details on the remaining nine defendants. Neither the Nigeria’s antigraft agency EFCC nor the Philippines Embassy could be immediately reached for comment Saturday.

The theft of Niger Delta crude costs Nigeria millions of dollars in lost revenue every year, with smugglers selling an estimated 100,000 barrels a day to foreign refineries.

In July, the navy arrested 14 Filipinos when another ship, the MT Lina Panama, was intercepted with stolen crude.

The Nigerian navy recently launched a new offensive against the theft of oil, widely referred to locally as “bunkering,” as millions of liters of crude or refined petroleum products are stolen annually.