By Richard Black
Environment correspondent, BBC News website
Britain's fisheries minister has summoned Iceland's ambassador to explain why the country has decided to start hunting endangered whales.
Iceland's decision has shocked anti-whaling governments
Ben Bradshaw called Iceland's position "inexplicable and inexcusable".
On Tuesday Iceland announced it would resume commercial whaling after a hiatus of 20 years.
Conservation groups are particularly angered by plans to hunt endangered fin whales; Iceland maintains numbers are high enough to permit hunting.
It disputes the assessment of scientists in IUCN, the World Conservation Union, that fin whale stocks are fragile.
But Mr Bradshaw disagreed. "World opinion is rightly outraged by this flagrant disregard for international agreements," he said.
"There is no rationale for this decision, and Iceland cannot even find markets for the whalemeat it gets from so-called 'scientific' whaling."
In diplomatic circles, summoning an ambassador is regarded as a fairly serious expression of displeasure.
But Stefan Asmundsson, Iceland's whaling commissioner, said his government was not concerned.
"Of course we want to have good relations with the UK and other countries around the world, and we're hopeful that while perhaps not agreeing with us they will see matters from our standpoint," he told the BBC News website.
"The British government's position is well known, and we understand where they're coming from, putting whales as a separate kind of animal that cannot be hunted; but we cannot accept that."
A global moratorium on commercial hunting has been in place for 20 years, with only Norway breaking it, having legally lodged a "reservation" to the moratorium when it came into force.
Since 2002 Iceland has been catching minke whales in the name of scientific research, as it is allowed to under International Whaling Commission (IWC) rules.
Whether it is legally entitled to resume commercial whaling is another matter.
Having left the IWC in 1992, it rejoined a decade later expressing a reservation to the moratorium, but anti-whaling countries believe this to have been illegal.
"Iceland's decision is extremely disappointing," said New Zealand's Conservation Minister Chris Carter.
"New Zealand will be making it very clear to the Icelandic government that we utterly reject their country's right to resume commercial whaling, and remain a part of the IWC."
But international reaction has not been entirely negative. Japan, which hunts more whales than any other country, welcomed Iceland's move.
"The size of Iceland's catch will in no way endanger the whale population," said Fisheries Agency official Hideki Moronuki.
Japan currently hunts for scientific research, but makes no secret of its desire for a return to commercial whaling.
At this year's IWC meeting it was able to push through a resolution, the first in 20 years, endorsing the eventual return of commercial fleets.
Some anti-whaling nations have vowed to step up diplomacy to prevent such a resumption.