The CEO of Sprint owner SoftBank said he'll start a "massive price war" if his company can purchase T-Mobile US.

Sprint is attempting to buy T-Mobile but hasn't reached an agreement yet. Even if it does, it could face opposition from a Federal Communications Commission that blocked AT&T's bid to purchase T-Mobile in 2011.

"We'd like to make a deal, but there are steps and details that we have to work out," SoftBank founder and CEO Masayoshi Son said on the Charlie Rose show this week. Rose suggested to Son that FCC Chairman Tom Wheeler might not want Sprint to buy T-Mobile because it would reduce wireless competition, but Son said that Sprint and T-Mobile today are "two little ones who are not able to fight without enough scale."

A combined Sprint/T-Mobile would turn the market into a "three heavyweight fight," Son said. "I would like to have the real fight, not a pseudo fight, the real fight," he said. "If I can have a real fight, I go in [with a] more massive price war."

Rose followed up by asking, "That's your pattern? You undersell everybody, you're willing to postpone profits in order to gain market share?"

"Exactly. I want to be #1," Son responded. "If we were #3, and if we had enough chance, I want to be #1."

The Wall Street Journal pointed out on Sunday that T-Mobile's aggressive moves haven't lowered bill prices across the industry. "Competition in the US wireless market has increased over the past year, but so have Americans' overall phone bills," the newspaper wrote. "While carriers have trimmed the price of their plans here and there in recent months, billings per user continue to grow amid a shift to smartphones and a surge in wireless Internet use. The results call into question the notion of a price war in the US market. Rather than aggressively compete outright on price, carriers are tailoring their moves to accomplish other goals as well, like weaning customers off expensive smartphone subsidies and encouraging them to use more data."

A recent survey found that Sprint customers' average bill price is $144 per month, second highest to Verizon Wireless's $148. Those numbers include both single users and family plan customers. T-Mobile's average price of $120 was lowest among the four major US carriers.