The defendants are accused of forcibly capturing the tanker in April after it set sail from Al-Mukalla port in southeast Yemen and battling Yemeni forces in an operation that left two cabin members killed.

The defendants, aged between 18 and 47, were present in the dock as the prosecution asked for the maximum penalty for hijacking the oil tanker and committing acts of banditry.

But in the absence of translators, the judge adjourned the trial to October 6.

Heavily-armed pirates using high-powered speed boats operate in the Gulf of Aden where they prey on ships, sometimes holding them for weeks before releasing them for large ransoms paid by governments or ship owners.

More than 150 suspected pirates were arrested by naval patrols in the region in 2008.

According to Ecoterra International, an NGO monitoring illegal maritime activities in the region, at least 163 attacks have been carried out by Somali pirates since the start of 2009 alone, 47 of them successful hijackings.

AFP