ANCHORAGE, Alaska (AP) - The U.S. Navy has started testing and training of submarines under sea ice off Alaska's north coast that takes place every other year.
Three U.S. submarines and a British sub will take part in the five-week exercise that the Navy calls ICEX 2018.
The Navy will set up a temporary command center camp on sea ice in the Beaufort Sea about 150 to 175 miles (242 to 282 kilometers) miles north of Prudhoe Bay to oversee the under-ice navigation and torpedo exercises.
Vessels participating include the USS Connecticut from Bangor, Washington, the USS Hartford from Groton, Connecticut, and the British Royal Navy's HMS Trenchant.
The last Arctic exercise by the U.S. Submarine Force was conducted in 2016.
A crack in ice through the camp forced an early evacuation.