Samsung on Wednesday unveiled a smartphone that folds open to become a tablet. Samsung is becoming the first major manufacturer to offer the feature as it strives to stoke excitement in a slumping market. The South Korean giant also appeared to get the jump on rivals by announcing the first smartphone for fifth-generation -- or 5G -- wireless networks, while stepping up its efforts in artificial intelligence and wearables.

The Galaxy Fold, unveiled at a San Francisco event, serves as a smartphone with a 4.6-inch display and opens like a book to become a 7.3-inch tablet. "We are giving you a device that doesn't just define a new category, it defies category," said Samsung's Justin Denison at the event. The Fold will be available April 26 starting at USD 1,980, the company said.