The regulators, which Google needs approval from to close the acquisition deal, also invited competitors and "interested third parties" to submit comments and observations on what it should do next. This move allows rivals to openly object to the deal, in what could be an anti-competitive matter.
But shares in Google fell nearly 4 percent at market close yesterday after poor expected financial results reflected on the company's bid to acquire the smartphone maker.
Google will be able to benefit in future patent litigation, as the search giant will acquire one of the largest patent portfolios in the telecommunications industry.
Motorola did not immediately respond to requests for comment.