Samsung has said it will halt the sale of its latest Galaxy Note 7 model over problems with the battery. It follows reports of the phone "exploding" during or after charging. In a statement, the company said it will take about two weeks to prepare replacement devices and it will change all phones sold to customers as well as retailers. It insists that there was a very minor problem in the battery cell production process. The replacement of Galaxy Note 7 phones will start September 19 in South Korea with 2.5 million devices sold to customers around the world so far.