FILE PHOTO: A smartphones with Sprint logo are seen in front of a screen projection of T-mobile logo, in this picture illustration taken April 30, 2018. REUTERS/Dado Ruvic/Illustration/File Photo GLOBAL BUSINESS WEEK AHEAD

WASHINGTON (Reuters) - The U.S. Justice Department has told T-Mobile US Inc TMUS.O and Sprint Corp S.N to wrap up a deal by the end of next week to sell assets that need to be divested or face a lawsuit aimed at stopping their proposed merger, a source familiar with the deal said on Thursday.

CNBC was the first to report the ultimatum.