The shootout broke out after rival gunmen disputed over the sharing of the huge ransom said to be nearly 7 million US dollars.
At least three pirates were killed and three others injured in the shootout on Monday evening.
The dispute started yesterday during the ransom payment when a group of pirates attacked pirates on board the MV Moran Centaurus, which was carrying about two million barrels of crude oil.
Local elders in Harardhere are tonight mediating the rival groups.
Somali pirates in Harardhere town fought over the ransom paid by the owners of the Greek-flagged ship Monday evening, witnesses told VOA Somali.