"To address the unforeseen increase in costs from our suppliers, we reluctantly must raise pricing on all products," the Nov. 26 letter to the chipmakers customers said. NXP confirmed the authenticity of the letter but declined to comment further.

Volkswagen AG said Friday that a global chip supply shortage could lead to interruptions in automobile production in China.

(Reporting by Stephen Nellis in San Francisco and Yilei Sun in Beijing; Editing by Chizu Nomiyama)