(Reuters) - French telecoms operator Iliad has made a buyout offer for T-Mobile USA Inc , the Wall Street Journal cited sources as saying, a surprise bid that counters an offer by Sprint Corp .
Details of the offer, which was made to T-Mobile's board, were unclear but the Journal cited one of its sources as saying it involved control of the company.
Shares in T-Mobile were up 4.5 percent at midday. Iliad and T-Mobile were not immediately available for comment.
(Reporting by San Francisco newsroom)
