UPDATE 4-U.S. Justice Department tells T-Mobile, Sprint it has concerns about merger deal -sources

The U.S. Justice Department has told T-Mobile US Inc and Sprint Corp it has concerns about their proposed $26 billion merger in its current structure, sources familiar with the matter said on Tuesday, although no final decision has been made.Sprint shares fell about 9 percent after the bell as investors increased bets the deal would not be completed following a Wall Street Journal report the merger is unlikely to be approved as currently structured.Shares of T-Mobile fell 4 percent.