WASHINGTON — The Obama administration is launching a fast-track review of Shell's troubled Arctic drilling efforts in the wake of a grounded drilling rig, a failed spill-equipment test and other problems.

But the administration made clear Tuesday that despite all the struggles, it still supports the controversial push to explore for oil in the waters off Alaska.

"The administration is fully committed to exploring for potential energy resources in frontier areas such as the Arctic," Interior Secretary Ken Salazar said.

The Interior Department will do an "expedited, high-level assessment," with a focus on Shell's numerous challenges, Salazar said in a written statement Tuesday. He said it will be led by Bureau of Ocean Energy Management Director Tommy Beaudreau and completed within 60 days.

Shell's drilling rig Kulluk broke free from its towline and was grounded for several days before being hauled off the rocks Sunday. It was on its way to Seattle at the time.

Shell's other drilling rig, the Noble Discoverer, has had safety and pollution issues and is the subject of an investigation. And in September, the spill-containment dome on Shell's response barge, the Arctic Challenger, was "crushed like a beer can" during testing off Washington state, according to an internal email from a federal regulator.

Shell spokesman Curtis Smith said Tuesday that the company welcomes the Interior Department's review. He said it would help Shell strengthen its efforts.

"While we completed our drilling operations off the North Slope safely and in accordance with robust permitting and regulatory standards, we nevertheless experienced challenges in supporting the program, especially in moving our rigs to and from the theater of operations," Smith said.

Environmental groups are calling for the Obama administration to immediately suspend Arctic drilling efforts.

The Coast Guard, meanwhile, said it will lead its own investigation into the grounding of the drilling rig. That's expected to take several months. Alaska Democratic Sen. Mark Begich, a supporter of offshore Arctic drilling, announced he plans to hold a hearing "at an appropriate date" into the failed towing of the drill rig.

The Obama administration let Shell begin preparatory drilling last summer in Alaska's Arctic waters, the first company to do so in two decades. Shell hopes to get permission to drill deeper this year.