T-Mobile US Inc. and Sprint Corp. are considering the divestiture of some airwaves to win Justice Department approval of their $26.5 billion merger, a proposal that's already attracted interest from Comcast Corp. and Charter Communications Inc., people with knowledge of the matter said.

Justice officials met Wednesday with Comcast and Charter over their possible interest in the airwaves and a potential role as a fourth wireless competitor, according to the people, who asked not to be identified because the talks are private. Both cable operators already offer wireless service.

T-Mobile and Sprint are scrambling to meet conditions sought by top Justice officials weighing whether to approve their merger, which would reduce the number of major wireless carriers to three from four.

The two wireless companies are considering divesting the airwaves to the government, which would sell them to help establish a fourth carrier, according to the people. Representatives from Comcast and Charter declined comment. There was no immediate response from Sprint, T-Mobile or the Justice Department.

Comcast and Charter, the two largest U.S. cable operators, told Justice officials they would bid on certain parts of the wireless business that might be divested as a condition of the deal, the people said. Both cable companies use Verizon Communications Inc.'s network to offer mobile phone service to their subscribers.

The cable companies are interested primarily in spectrum, as well as favorable wholesale agreements, network equipment and customers that might be part of the divestiture, according to the people.