U.S. regulators asked for more information about Verizon Wireless’s proposed $3.6 billion purchase of airwaves from cable companies led by Comcast Corp.

The Federal Communications Commission posted queries to Verizon, Comcast and second-largest U.S. cable operator Time Warner Cable Inc. on its website Thursday.

Verizon and the cable companies announced an accord for the purchase of unused airwaves in December, and also said they had agreed to sell each others’ services.

The Justice Department is looking into the marketing deals, and the FCC today said it will review parts of the agreements as it examines the airwaves sale.

Verizon Wireless, based in Basking Ridge, New Jersey, is 55 percent owned by Verizon Communications, with the remainder held by Newbury, United Kingdom-based Vodafone Group Plc.