Two historic Oahu military bases have formally merged.

Naval Base Pearl Harbor and Hickam Air Force Base became one installation Friday.

They're among 26 installations across the country that are combining to become 12 joint bases as the military strives to become more efficient.

Joint Base Pearl Harbor-Hickam commander Capt. Richard Kitchens says it's a challenge to bring 1,100 civilian Air Force employees to the Navy's human resources system. But he says officials are anticipating and addressing potential problems.

Pearl Harbor and Hickam have been close but distant neighbors for decades. They're right next to each other on Oahu's southern edge, but each has its own school, golf course, bowling alley, church and other facilities.