A federal judge has ordered the Bush administration to decide by May 15 whether polar bears should be protected as an endangered species, due to the effects of global warming.

The administration was supposed to take this decision in December 2006, when the sea ice, on which polar bears depend on for survival, started shrinking dramatically due to climate change.

Officials have delayed the problems for several months and U.S. District Judge Claudia Wilken agreed with the conservation groups that criticized the administration that the interior department had missed the Jan. 9 deadline for a decision. Wilken rejected Interior Secretary Dirk Kempthorne's proposal of delaying the decision until June 30.

"Defendants have been in violation of the law requiring them to publish the listing determination for nearly 120 days," the judge wrote in a statement released Monday. "Other than the general complexity of finalizing the rule, Defendants offer no specific facts that would justify the delay, much less further delay."

A decision to consider polar bears as an endangered species could restrict oil and gas exploration in the US Arctic, a situation that the Bush administration kept trying to avoid.

The judge's ruling pleased the conservation groups that blamed the administration for failing to address the consequences of global warming, which lead polar bears toward extinction.

"We hope that this decision marks the end of the Bush administration's delays and denial so that immediate action may be taken to protect polar bears from extinction," Greenpeace representative Melanie Duchin said in a statement.

Summer sea ice shrank dramatically last year, and a U.S. Geological Survey study predicted that polar bears in Alaska could be extinct by 2050.