Dozens of anti-globalisation activists plunged into the sea to get their message across in Hong Kong where a World Trade Organisation conference is underway.
They are among around 2,000 people who have gathered to protest against the talks aimed at securing a global trade agreement.
There have already been some minor clashes outside the venue – several people are reported to have been injured and a number arrested.
The six-day summit was initially intended to agree a deal on a new draft trade treaty. But delegates from rich and poorer nations are deeply divided over agriculture subsidies and tariffs.
The EU has faced intense pressure to make deeper cuts in tariffs than the average 39 percent it has offered. But it is refusing to move further without pledges from developing states to open their markets to industrial goods.
WTO chief Pascal Lamy joked that someone had lent him a magic wand but that he did not think it was going to work very well. “The magic only works if all the world believes in it,” he said in his address. The conference was disrupted for a short time by protestors who had managed to get inside the hall.
Outside, the police acted swiftly after demonstrators set fire to a mock coffin symbolising the death of the WTO.
But, so far, there has been none of the intense violence seen during the last WTO meetings in Cancun in Mexico and Seattle in the US.