Image caption The polar bear was classified as "threatened" by the US administration of former President George W Bush

Environmental campaigners in the US have lost a battle to have the polar bear listed as an "endangered" species.

The US department of the interior has upheld a decision to classify the bear as "threatened" - a status that gives them less protection under the law.

The government said it did not find that polar bears were on the brink of extinction, needed to qualify for the status of "endangered".

Environmental campaigners have said they will challenge the decision.

'Anti-science decision'

Under the Endangered Species Act, the status of "endangered" requires the government to assess the impact of greenhouse gases on the bears' Arctic homelands.

When the government is considering permits for oil development in northern Alaska, it must include greenhouse gas emissions in its decision.

When the polar bear was listed as "threatened" by the administration of former US President George W Bush, officials invoked a special rule saying the Endangered Species Act could not be used to regulate greenhouse gas emissions.

So an "endangered" listing is a more powerful tool for limiting industrial activity that causes greenhouse gases.

The Centre for Biological Diversity - one of the groups trying to get the polar bear listed as "endangered" - said the ruling showed that the administration of US President Barack Obama was continuing to defend Bush-era "anti-science decisions".

It says polar bears face an 80% chance of extinction within 40 years and it will continue to challenge the US government in court.