The UN's International Maritime Organisation (IMO) has issued guidelines on the management, types of weapons, ammunition, insurance and rules of engagement between the ship-owner, the master and security contractor on ships in pirate-threatened waters off Somalia and the Indian Ocean.

The IMO maritime safety committee has outlined the use of guards for a flag state after it has exhausted defensive measures under the rubric of “best practice”, such as stringing barbed razor wire around the gunwales, evasive tactics and the use of water cannon and sound guns, reported London's International Freighting Weekly , which adds that the guidelines do not address the legal issues.

The IMO only says that any laws and regulations of the flag state, port and coastal states will also apply to the use of onboard security.

A review of the interim recommendations will take place in September by a working group on maritime security and piracy.