Updated

Officials in Gabon say pirates hijacked an oil tanker with a 20-person crew near the main port where oil is loaded for transport to international markets.

Defense Minister Pacome Rufin Ondzounga and Interior Minister Jean Francois Ndoungou said in a statement distributed Wednesday night that the attack occurred early Monday.

Security firm AKE said the attack constituted "a significant expansion" of the area affected by piracy in the Gulf of Guinea, occurring 200 nautical miles further south than a previous attack in April. The firm said all contact had been lost with the Indian crew aboard the Malta-flagged tanker, which is operated by the Turkish firm Geden Lines.

The International Maritime Bureau warned earlier this week of a "worrying surge" of attacks by pirates in the Gulf of Guinea.