Russia released two killer whales and six beluga whales back into the wild on Thursday, the first group of almost 100 whales whose detention in the Far East since last year caused an international outcry.

The whales, caught last summer in order to be sold to marine parks or aquariums in China, were released in the Gulf of Sakhalin, part of their natural habitat in the Sea of Okhotsk, a Russian oceanography research institute said in a statement.