Samsung, South Korea's largest conglomerate, says an internal investigation has revealed thatfaulty batteries are responsible for the fires that hit its flagship Galaxy Note 7 smartphone last year, causing a nosedive in the company's profits and a serious swipe to its reputation. Koh Dong-jin, chief of Samsung's mobile division, bowed as he apologized at a press conference Monday in Seoul.He said, "From now on, our first priorities will be product quality and customer safety." Samsung was forced to take the device off the market after replacement phones also caught fire. The smartphones were in the headlines last year when their fires injured people, destroyed a car and caused the evacuation of a Southwest Airlines flight. Analysts say the drive to produce a thin phone with longer battery life may have contributed to Samsung's woes. The company said in a statement that "We have taken several corrective actions to ensure this never happens again.The lessons of the past several months are now deeply reflected in our processes and in our culture." Samsung is expected to release another smartphone soon.