Sea robbery is a term used to describe attacks upon commercial vessels in ports and territorial waters. Such attacks are, according to international law, not true acts of piracy but rather armed robberies. They are criminal assaults on vessels and vessel crews, just as may occur to truck drivers within a port area. Such attacks pose a serious threat to trade. The methods of these attacks have varied from direct force using heavy weapons to subterfuge in which the criminals have identified themselves on VHF radio as the national coast guard.These maritime criminals are inclined to operate in waters where government presence is weak, often lacking in both technical resources and the political will to deal effectively with such attacks. International law permits any warship or government vessel to repress an attack in international waters. In a state's territorial waters, such attacks constitute an act of armed robbery and must be dealt with under the laws of the relevant coastal state. These laws seldom, if ever, permit a vessel or warship from another country to intervene. The most effective countermeasure strategy is to prevent criminals initial access to ports and vessels, and to demonstrate a consistent ability to respond rapidly and effectively to notification of such a security breach. Acts of piracy can only be committed by private ships or private aircraft. A warship or other public vessel or a military or other state aircraft cannot be treated as a pirate unless it is taken over and operated by pirates or unless the crew mutinies and employs it for piratical purposes. By committing an act of piracy, the pirate ship or aircraft, and the pirates themselves, lose the protection of the nation whose flag they are otherwise entitled to fly. To constitute the crime of piracy, the illegal acts must be committed for private ends. Consequently, an attack upon a merchant ship at sea for the purpose of achieving some criminal end, e.g., robbery, is an act of piracy as that term is currently defined in international law. Conversely, acts otherwise constituting piracy done for purely political motives, as in the case of insurgents not recognized as belligerents, are not piratical. International law has long recognized a general duty of all nations to cooperate in the repression of piracy. This traditional obligation is included in the 1958 Geneva Convention on the High Seas and the 1982 LOS Convention, both of which provide: "[A]ll States shall cooperate to the fullest possible extent in the repression of piracy on the high seas or in any other place outside the jurisdiction of any State."
It is widely accepted among the government and non-government organizations that track piracy worldwide (including the U.S. Office of Naval Intelligence (ONI), U.K. Defense Intelligence Service (DIS), Australian Defence Intelligence Organization (DIO) and the International Maritime Bureau (IMB)), that the annual number of piracy cases is seriously undercounted. DIS estimates the actual number of piracy cases could be 2,000 percent higher on an annual basis while DIO estimates the underreporting to be 20 to 70 percent.44 Since the establishment of the IMB's Regional Piracy Center in Malaysia in 1992 and its subsequent efforts to publicize the piracy problem, there has been increased reporting on major incidents, but incidents involving fishermen and recreational boaters are still heavily undercounted. Also, the average loss from a piracy incident does not cross the monetary threshold for insurance action, further contributing to underreporting. Most incidents will continue to go unreported except in cases where there is serious loss of property and life or damage to a foreign interest.The concentration of piracy incidents continues to be located in areas with little or no maritime law enforcement, political and economic stability, and a high volume of commercial activity. Incidents of piracy tend to occur in four regional areas: Southeast Asia, Africa, South America, and Central America. Furthermore, most incidents of maritime crime occur in coastal waters with nearly 80 percent of all reported piracy incidents occurring in territorial waters.