The U.S. Department of Justice has given the green light to the merger of T-Mobile USA and MetroPCS but the deal still needs approval from the Federal Communications Commission, the Committee on Foreign Investment in the United States (CFIUS), and MetroPCS shareholders, according to T-Mobile USA parent company Deutsche Telekom.

Final approval of the proposed merger could happen on April 12, when those three groups are scheduled to meet, Reuters reported Wednesday(Opens in a new window).

Last October, T-Mobile USA and MetroPCS announced plans to “combine forces” to “create the leading value carrier in the U.S. wireless marketplace.”

Meanwhile, T-Mobile USA employees at the carrier’s headquarters in Bellevue, Wash. are girding themselves for “a significant round of layoffs” ahead of a merger with MetroPCS that appears to be on the fast track, if not necessarily a fait accompli at this point, according to The Seattle Times(Opens in a new window).

Unnamed sources within the company said the layoffs are expected to happen Thursday and could affect “more than 100 people in marketing and other groups,” the newspaper reported, adding that conference rooms at T-Mobile’s Bellevue campus have been reserved on Thursday for “integration meetings.”

T-Mobile USA, a subsidiary of Deutsche Telekom’s T-Mobile International, has been consolidating its U.S. call centers and strategically downsizing for the past few years as the company prepared first for a proposed acquisition by AT&T that ultimately failed and then the current MetroPCS merger bid.

The carrier cut more than 4,200 jobs its call centers and in other parts of the company in 2012 but mostly spared the nearly 5,000 staff members employed at its headquarters, The Seattle Times noted.

The merger with MetroPCS may be on the fast track, but it’s by no means a done deal, according to reports. Some MetroPCS shareholders, including major stakeholders Paulson & Co. and and Schoenfeld Asset Management, are reportedly on the fence about the deal if not outright hostile to it, TechSpot noted Wednesday(Opens in a new window).