Published: Oct 14, 2012 6:16 PM EDT
Updated: Oct 15, 2012 6:30 AM EDT

WASHINGTON (AP) - Japanese mobile phone company Softbank is agreeing to buy 70 percent of Sprint Nextel Corp. for $20 billion, according to a news report.

The deal is expected to be announced Monday, according to CNBC's web site, which cited anonymous sources "close to the situation."

The transaction could make Sprint, the third-largest U.S. mobile phone company, a tougher competitor against its bigger rivals, Verizon Wireless and AT&T. Sprint has 56 million subscribers, about half the amount of Verizon Wireless, the leading provider.

Softbank will buy $8 billion in shares from Sprint and another $12 billion from current Sprint shareholders, the CNBC report said.

John Taylor, a spokesman for Sprint, declined to comment beyond the company's statement last week confirming that it was in talks with Softbank.