It said the number of siphoning attacks had escalated since April 2014, with 15 attempts in the region last year.

ReCaap said it is concerned by the trend and has been working closely with the shipping industry, government agencies and international organisations to highlight best practice in combating the threat.

Crew are often locked up and communication equipment smashed during the attacks, carried out on small tankers in hours of darkness by men carrying guns and knives

ReCaap has identified at least three organised groups of pirates carrying out the attacks and said crime syndicates are also likely to be involved.

It