Copenhagen - Activists from environmental group Greenpeace Tuesday tried to board a ship loaded with coal between the main Danish islands of Zealand and Fyn.
The protest, staged in two dinghies, was timed to coincide with the UN climate change conference that opened Monday in Poznan, Poland.
The 300-metre long vessel was loaded with coal from South Africa and was headed for Aabenraa where Danish energy group Dong Energy operates a coal-fired plant.
Greenpeace said it was "shameful" that Denmark each year imports some 8.3 million tons of coal, generating 19 million tons of carbon dioxide (CO2).