Justice Department officials recently told Sprint board members that a Sprint acquisition of T-Mobile US "could face regulatory difficulties," The Wall Street Journal reported Tuesday night.

Sprint is laying the groundwork for a bid on T-Mobile that could leave the US with only three major cellular carriers. This comes more than two years after AT&T's attempt to buy T-Mobile was dropped because of opposition from the Justice Department and Federal Communications Commission.

"Sprint Corp. board members Masayoshi Son and Dan Hesse met recently with Justice Department officials who said they would view a Sprint acquisition of wireless rival T-Mobile US Inc. with skepticism, people briefed on the conversation said," the Journal reported.

"The message from regulators shouldn't have come as a surprise," the newspaper noted. "In April, the Justice Department wrote in a comment letter to the FCC that the four wireless carriers competed in ways that are important to consumers. The FCC has sent similar signals."

Son is the CEO of Sprint's new corporate parent Softbank. The Japanese executive, described as "the driving force behind the effort to merge Sprint... with T-Mobile," has apparently not been deterred by the meeting with US officials.

T-Mobile US CEO John Legere has positioned his company as a kind of rebel or "un-carrier" in the wireless industry, but he hasn't opposed the potential Sprint/T-Mobile merger. When asked about the potential merger, he said it might help create a formidable rival to Verizon Wireless and AT&T.

“We all need better scale and capability,” Legere told Bloomberg. "The question starts to be: How do you take the maverick and supercharge it? We either need more spectrum and capability and a lot more investment, or we need consolidation.”

T-Mobile continued its "maverick" ways this week, issuing a mock press release that contained fake quotes from AT&T Mobility CEO Ralph de la Vega and an apparently real quote from Legere comparing AT&T to Darth Vader.