Naval forces off Somalia must take firm action to tackle the vessels pirates are using as bases for long-range attacks, shipping organisations said on Tuesday after the weekend’s audacious seizure of a huge oil tanker.

Since the weekend hijack of the Saudi tanker, pirates have seized two more ships – a Greek bulk carrier, in the Gulf of Aden with about 25 crew on board, and a Hong Kong-flagged ship carrying grain and bound for Iran. The Indian navy said on Wednesday one of its warships deployed in the Gulf of Aden had fought Somali pirates and destroyed their vessel after a brief battle.