Australia ? Australia said Wednesday that Japan has agreed to release two activists detained after going aboard a Japanese whaling ship near Antarctica, as whale hunters and defenders traded accusations of piracy.

The Japanese whalers accused the activists of attacking their vessel with bottles of acid and illegally boarding the Yushin Maru No. 2 on Tuesday and denied claims the men had been assaulted and tied up on deck.

The anti-whaling group Sea Shepherd said the pair – Australian Benjamin Potts, 28, and Briton Giles Lane, 35 – boarded the ship to deliver a letter demanding an end to the hunt, but had been roughed up and were being held against their will.

The standoff drew criticism from Australian Foreign Minister Stephen Smith, whose officials contacted their Japanese counterparts late Tuesday to seek the release of the two activists.

The event was a rapid escalation of the annual contest between the fleet that carries out Japan’s controversial whale hunt in the ocean at the bottom of the world and the environmental groups who try to stop them.