Environmental groups filed a lawsuit over plans to conduct sonar testings and live-fire training off Hawaii and California waters.
The federal court lawsuit points to the Navy's own environmental impact studies that say that up to 2,000 whales and dolphins could be seriously hurt by testing conducted over the next five years.
"That's going to have some disastrous effects for marine mammals in our waters. You're looking at over the next five year period 155 killed marine mammals," said David Henkin, staff attorney for Earthjustice, which filed the suit on behalf of five environmental groups.
The suit was filed against the National Marine Fisheries Service, which last week approved a Navy environmental study for the sonar and explosives training. The Navy's previous five-year permit expires in January.
Scientists have linked sonar to mass beachings along with animal injuries and deaths. Attorneys for the environmental groups raised concerns about the impact of the sonar testing on rare humpback whales, false killer whales and the Hawaiian monk seal
The Navy has promised to halt its training when mammals are sighted but environmentalists say they want to Navy to stop doing these tests in areas where the endangered whales, dolphins and seals inhabit.
The Navy had no immediate comment on the lawsuit.
The suit was filed by the Conservation Council for Hawaii, the Animal Welfare Institute, the Center for Biological Diversity and the Ocean Mammal Institute.