The US Justice Department announced tough limits Thursday on Verizon\'s effort to expand its wireless entertainment footprint, amid worries the cellphone and cable giant was building a monopoly. The department put limits on Verizon\'s marketing activities while approving its purchase of wireless spectrum from major cable television rivals Comcast, Time Warner Cable and Bright House Networks. The department also placed limitations on the companies\' plans to cooperate in their respective markets by bundling their products together as a part of the spectrum deal. It also said Verizon had agreed to divest some of the spectrum to a smaller cellphone competitor, T-Mobile. The $3.6 billion deal announced by the four last December sparked antitrust lawsuits over fears that by packaging their products together, the four would lock out competition in cable markets. Regulators also feared that the joint marketing would give Verizon a dominant position in the rapidly growing 4G LTE-standard wireless broadband and video market. The sector has been booming as online streaming has improved in quality and as more customers buy tablet computers that are well-suited to multimedia consumption. \"By limiting the scope and duration of the commercial agreements among Verizon and the cable companies while at the same time allowing Verizon and T-Mobile to proceed with their spectrum acquisitions, the department has provided the right remedy for competition and consumers,\" said Joseph Wayland, who heads the Antitrust Division of the Justice Department.