The U.S. Federal Trade Commission on Wednesday cleared Pfizer Inc.'s (PFE) $68 billion deal to acquire rival Wyeth (WYE), but required the companies to divest assets in the animal-health market as a condition of government approval.

With the FTC's clearance, Pfizer said it expects to close the transaction on Thursday.

The FTC said the divestitures will protect competition in the market for animal vaccines and other animal health products.

The commission found no competitive concerns about the merger's effect on human-health products, saying the deal likely wouldn't harm consumers in any prescription drug market. The FTC said the two companies' product portfolios were highly complementary.

"Although the commission, based on the evidence gathered, determined that this transaction did not raise anticompetitive concerns in the markets for human pharmaceuticals, the commission remains dedicated to ensuring that pharmaceutical markets are competitive," the FTC said in a written statement.

The Pfizer-Wyeth deal, announced in January, received approval from the European Commission in July.

"We are pleased to have received all of the requisite regulatory approvals for our combination with Wyeth," Jeffrey Kindler, Pfizer's chairman and chief executive, said in a statement.

"We now look forward to combining the two companies so that we can achieve meaningful results for patients, customers and the communities we serve, as well as for our shareholders."

A Wyeth spokesman declined immediate comment.

As part of its settlement with the commission, Pfizer has agreed to sell half of Wyeth's Fort Dodge U.S. animal-health business to Boehringer Ingelheim Vetmedica, Inc., within 10 days of the acquisition.

Pfizer and Wyeth announced the animal-health agreement with Boehringer Ingelheim last month.

Assets to be sold include vaccines for cattle, dogs and cats.

-By Brent Kendall, Dow Jones Newswires; 202-862-9222; brent.kendall@dowjones.com

(Peter Loftus contributed to this article.)