China has launched an unusual charm offensive to explain its first overseas naval base in Djibouti, seeking to assuage global concerns about military expansionism by portraying the move as Beijing's contribution to regional security and development.

The message is in stark contrast to Beijing's more bellicose stance on the South China Sea, where its claims on a vital trade waterway have raised hackles across Asia and the United States.

China has repeatedly said it does not seek a U.S.-style "hegemony" by extending its military reach, including through bases abroad.