Millions of dollars of cocaine packed in a plastic drum has washed up on a seashore in the eastern Philippines, an anti-narcotics official said Friday.

A local fisherman in the town of Matnog, Sorsogon found the drum on Wednesday and reported it to authorities, not knowing what was inside, said Christian Frivaldo, a regional director of the Philippine Drug Enforcement Agency.

Inside the drum, anti-drug agents found about 24 kilograms (53 pounds) of cocaine bricks wrapped in plastic, he told AFP.

Frivaldo estimated the value of the cocaine at about 125 million pesos ($2.5 million).

• BASAHIN: 24 pakete ng hinihinalang cocaine, nasabat sa baybayin sa Sorsogon

The source of the cocaine found in Matnog -- about 403 kilometers (250 miles) southeast of the capital Manila -- may be a Taiwan-flagged cargo vessel that was hit by huge waves off the eastern Philippines a day before the cocaine was found, he said.

Nine Chinese, Hong Kong and Taiwanese crewmen are under the custody of the local government after they were rescued from their damaged ship, he added.

"They are under investigation. We are checking their vessel (to see) if there is additional evidence inside. But it is difficult because it is half-submerged," Frivaldo said.