SOMALI pirates seized another merchant ship in the Indian Ocean on Monday.

It brought the total number of vessels currently being held to 23.

The MV Orna was attacked at midday local time approximately 400 nautical miles north east of the Seychelles, according to the EU's anti-piracy naval force Navfor.

The assault was launched from two attack skiffs, with pirates firing small arms and rocket propelled grenades at the merchant vessel. At least four pirates boarded. The crew was cooperating and no damage was reported.

The MV Orna is a Panama-flagged, bulk cargo vessel with a dead weight of 27,915 tonnes. The number of crew on board was unknown. The vessel is owned and operated by the United Arab Emirates.

The European Union confirmed recently that pirates operating off Somalia were holding well in excess of 500 hostages following hijackings in the vulnerable waters of the Gulf of Aden and Indian Ocean.

The EU Navfor mission, which is tasked with escorting merchant vessels carrying humanitarian aid, also protects general shipping and disrupts piracy off the coast of Somalia, which has become a refuge for criminal gangs who demand massive ransoms before they release their captives.