The FTC has assembled an internal litigation team to prepare for a possible effort to block the deal, sources familiar with the matter told the newspaper.

The FTC also has sent letters to AdMob's competitors asking them to testify in sworn statements about the potential impact of the acquisition. The regulator also has briefed Congress on its concerns, the Journal reports.

Five FTC commissioners, however, are yet to vote against the deal and Google lawyers continue to meet with the agency's staff to debate in favor of the acquisition, and the two sides could yet come to an agreement to allay FTC's concerns and preserve the deal.

Source: thestreet