The Mexican Navy says a helicopter carrying four crew members has gone missing over an area of western Mexico where drug cartels are active.
The Navy crafts has been missing since it set out four days ago from the Pacific coast city of Manzanillo on a trip to the city of Morelia, the capital of Michoacan state.
Civilian and military officials are searching for the Eurocopter Panther helicopter in an area around Michoacan.
The Navy said in a statement Tuesday that the missing helicopter had lost radio contact with controllers on Friday. It does not say what might have caused the craft to disappear.
Mexican armed forces and prosecutors suffered at least 28 gunfire attacks on helicopters in the first five years of the government offensive against drug cartels.