Angolan state oil firm Sonangol said on Friday that search teams were scouring the Atlantic off the coast of Luanda Friday for a lost Greek oil tanker feared hijacked by pirates.
"The relevant authorities have already been alerted and launched conventional technical mechanisms to locate the vessel and identify the reasons for its disappearance," the firm said in a statement.
Earlier this week Athens-based Dynacom Tankers Management said it had lost communication with the tanker Kerala, which has a crew of 27 Indians and Filipinos, since Saturday.
It had just taken on a diesel shipment for Sonangol Shipping, a subsidiary of the state oil company, at Luanda's port.
Angola's coastguard told local media it was scouting for the ship, without commenting on reports of a hijacking by pirates.
If confirmed, it would be the southernmost attack in the Atlantic Ocean off the West African coast.
Dynacom and other observers fear this could signal Nigerian pirates' expansion from the Gulf of Guinea.
Angola is the second largest oil producer in Africa after Nigeria.