A Japanese whaling ship joined in the search for two anti-whaling activists who went missing during a confrontation in icy seas off Antarctica.
Activists vow to continue pursuing Japanese whaling ships
A temporary truce was called during a joint, eight-hour search for the two members of the conservation group Sea Shepherd, who were later recovered.
The pair became lost during a clash in which the activist group splashed acid onto the deck of the whaling ship.
The Japanese government called the actions "piratical" and "dangerous".
The incident happened in the early hours of Friday, after the activist ship The Farley Mowat caught up with Japan's Nisshin Maru whaling ship.
The US-based Sea Shepherd group said its activists managed to douse the deck of the whaler with six litres of non-toxic but foul smelling butyric acid.
During the confrontation, US activist John Gravois and Australian activist Karl Neilsen became lost in the heavy fog and snow.
Mr Gravois later told the Australian Associated Press that their inflatable dinghy was damaged after it collided with the whaling ship and they quickly fell behind the group.
He said they managed to tie their boat to an iceberg to stop themselves from drifting, while they awaited rescue.
"When they found us it was a feeling of the most extreme relief that you can image," he said.
They were eventually found by the Farley Mowat, but the activists had earlier asked for help in the search from the Nisshin Maru.
"They were willing to do that - (it's) nothing we wouldn't do for them as well," said Johnny Vasic, international director of the Sea Shepherd group.
"It's a kind of rule of the sea and sailors."
He said they had thanked the Japanese whalers for their help, but that they would continue to pursue them.
Mr Vasic also defended the tactic of pouring acid on to the ships, saying it had no harmful effects other than smelling bad and was aimed to disrupt the whalers' work.
"That's one of our tactics, to wake them up to the smell of rotting flesh while is all over their ships," he told the BBC from on board one of the activist ships.
A spokesman for the Japanese Foreign Ministry told the BBC that he was outraged that Japan's ships had been attacked in this way.
He pointed out that all the members of the International Whaling Commission had agreed to try to prevent incidents like this taking place.
Japan says it plans to cull 850 minke whales this winter and 10 fin whales, as part of what it calls its programme of scientific research.
Sea Shepherd and Greenpeace have vowed to do all they can to disrupt the hunt.