AGADIR, Morocco – An international effort to truly limit whale hunting collapsed Wednesday, leaving Japan, Norway and Iceland free to keep killing hundreds of mammals a year, even raiding a marine sanctuary in Antarctic waters unchecked.

The breakdown put diplomatic efforts on ice for at least a year, raised the possibility that South Korea might join the whaling nations and raised questions about the global drive to prevent the extinction of the most endangered whale species.

It also revived doubts about the effectiveness and future of the International Whaling Commission. The agency was created after World War II to oversee the hunting of tens of thousands of whales a year but gradually evolved into a body at least partly dedicated to keeping whales from vanishing.

“I think ultimately if we don’t make some changes to this organization in the next few years it may be very serious, possibly fatal for the organization — and the whales will be worse off,” former New Zealand Prime Minister Geoffrey Palmer told the hundreds of delegates.

Japanese officials and environmentalists traded charges of blame after two days of intense, closed-door talks failed to break a deadlock in which the three whaling nations offered to limit their catch but refused to phase it out completely.

About 1,500 animals are killed each year by the three countries. Japan, which kills the majority of whales, insists its hunt is for scientific research — but more whale meat and whale products end up in Japanese restaurants than in laboratories.

A key sticking point is the sanctity of an ocean region south of Australia that the agency declared a whaling sanctuary in 1994. Despite that declaration, Japanese whalers regularly hunt in Antarctic waters.