U.S. satellite TV company Dish Network Corp. has asked the Federal Communications Commission to suspend its evaluation of Softbank Corp.'s bid for U.S. cellphone provider Sprint Nextel Corp., sources said Thursday.

The announcement of Dish's $25.5 billion bid for Sprint on April 15 constituted an important development that has generated uncertainty about Softbank's bid, Dish said in a filing with the FCC.

Dish told the regulator that its bid would be more advantageous for U.S. consumers, Sprint's shareholders and national security than the Softbank bid.

The FCC has been reviewing Softbank's bid since October, when it proposed acquiring 70 percent of Sprint's shares for $20.1 billion. The Dish bid is now before the board of directors of the Kansas-based cellphone service provider.

In response to Dish's move, Softbank has said its agreement to acquire Sprint should be considered a done deal.

The third-largest mobile phone service provider in Japan also said the Dish proposal is highly conditional and "believes that the agreed terms of our transaction with Sprint offer Sprint shareholders superior short- and long-term benefits."