ANCHORAGE Interior Secretary Ken Salazar says the Minerals Management Service has conditionally approved plans by Shell Oil Co. to drill exploratory wells in the Chukchi Sea.

The plan by Shell Gulf of Mexico Inc. 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. Shell's subsidiary in 2008 paid $2.1 billion for leases in the Chukchi.

Drilling is strongly opposed by environmental groups because of the risk of spills in a sensitive marine ecosystem stressed by climate change.

On Monday, Alaska's congressional delegation praised the decision.