The waters between the Red Sea and the Indian Ocean, off the Somali coast and in the Strait of Malacca and Singapore have frequently been targeted by modern pirates armed with automatic weapons, such as assault rifles, and machine guns, grenades and rocket propelled grenades. They often use small motorboats to attack and board ships, a tactic that takes advantage of the small number of crew members on modern cargo vessels and transport ships. The international community is facing many challenges in bringing modern pirates to justice, as these attacks often occur in international waters.[7] Nations have used their naval forces to repel and pursue pirates, and some private vessels use armed security guards, high-pressure water cannons, or sound cannons to repel boarders, and use radar to avoid potential threats.