Deutsche Telekom has agreed to an offer for Japanese mobile and broadband company SoftBank to buy T-Mobile USA, according to a news report.

Japanese news site Kyodo News, which reported the agreement, didn’t give details of the price or structure of the deal.

The deal would combine SoftBank-owned Sprint, the third largest U.S. mobile carrier, with T-Mobile, the fourth largest. The combined company would have more than 103 million subscribers, but it would still be No. 3 behind Verizon Wireless, with about 122 million subscribers, and AT&T, with 116 million.

SoftBank CEO Masayoshi Son has pushed for a merger between Sprint and T-Mobile, saying a combined company is necessary to successfully compete with the two largest mobile carriers. A combined company would be able to invest in its network and push AT&T and Verizon on prices and services, he has said.

U.S. officials at the Federal Communications Commission and the Department of Justice have raised competitive concerns about a potential merger between Sprint and T-Mobile USA. Both agencies would have to approve the deal.

Officials with Deutsche Telekom and SoftBank weren’t available for comment.

SoftBank’s $21.6 billion acquisition of Sprint closed last July.