ANCHORAGE, Alaska — The Minerals Management Service conditionally approved plans by Shell Oil Co. to drill exploratory wells in the Chukchi Sea, said Interior Secretary Ken Salazar.

The Obama administration had delayed a decision on whether to allow to drilling in the icy sea because it is a prime habitat for threatened polar bears.

The plan by Shell calls for three exploratory wells next year in waters off Alaska's northwest coast.

Salazar calls approval of the exploration plan a cautious but deliberate step toward developing additional information on the Chukchi Sea.

There was a flood of public comment sent to the Minerals Management Service, an arm of the Interior Department, when it was learned that Shell wanted to drill in the region.

Lawmakers from Alaska meet with Salazar earlier this month and urged approval for the project, saying that Shell Oil had spent more than $2 billion for exploration rights in the Chukchi.

The Department of Justice is already looking into oil leases elsewhere that were issued to parent company Royal Dutch Shell PLC. Investigators are trying to determine if the interior secretary under President George Bush steered contracts toward the company.

Gale A. Norton, the former interior secretary, resigned her position and took a job with Shell.