Son, speaking at an annual SoftBank shareholders' meeting in Tokyo, said his company was on track to acquire Sprint by July, as long as its $21.6 billion bid is approved by both Sprint shareholders and the U.S. Federal Communications Commission.

Son also said the fierce bidding war for Sprint with U.S. satellite TV provider Dish Network Corp had prompted his company to consider various other options, including buying No. 4 U.S. mobile carrier T-Mobile, which is 74 percent owned by Deutsche Telekom AG.

(Reporting by Mari Saito; Writing by Sophie Knight; Editing by Edmund Klamann)