Washington ? Regulators agreed Monday to approve SBC Communications’ takeover of AT&T and Verizon Communications’ purchase of MCI – deals that allow the nation’s biggest phone companies to grow bigger.

By 4-0 votes, the Federal Communications Commission approved the multibillion-dollar mergers with conditions.

The agency required that SBC and Verizon freeze for 30 months the wholesale prices they charge competitors to lease certain high-capacity business lines. It said the two companies had to guarantee for two years that they will sell their high-speed Internet access as a stand-alone service, so customers aren’t forced to buy local phone service as well.

In order to gain approval, the companies also promised not to hinder Internet access to consumers or the free flow of Internet traffic on their networks.