Animal rights activist Paul Watson, freed this week from detention in Denmark, vowed on Saturday to end whale hunting worldwide and to stop Japan if it tried to resume whaling in the Southern Ocean.

Watson, a 74-year-old Canadian-American, returned to France on Friday after spending five months in detention in the Danish autonomous territory of Greenland due to an extradition demand from Japan.

"One way or the other we are going to end whaling worldwide," Watson told reporters in central Paris where several hundred supporters had gathered to greet him.