The clearance, which comes about a week after the U.K. Office of Fair Trading the deal, paves the way for Facebook to complete the acquisition of the online photo-sharing company.

After the FTC clearance, Facebook does not have any antitrust reviews pending on the proposed acquisition, a spokesman said.

FTC said in a statement that it had voted 5-0 to close its nonpublic investigation into the antitrust implications of the proposed acquisition.

"We are pleased that the Federal Trade Commission has cleared the transaction after its careful and thorough review," Facebook said in a statement.

Facebook that it was buying Instagram for US$1 billion in cash and stock. It subsequently clarified that it would pay $300 million in cash and close to 23 million shares of its common stock. "The value of the equity component of the final purchase price will be determined for accounting purposes based on the fair value of our common stock on the closing date," Facebook said in a regulatory filing in end July. At current prices of its shares, which have seen a drop, the deal could be more in the $750 million range.