Tribune Publishing, the parent company of The Los Angeles Times, won an auction for The Orange County Register and The Riverside Press-Enterprise this week with a bid of $56 million in cash, the company said on Thursday, though the acquisition still faces several hurdles before it can proceed.

A few hours after the announcement, the Justice Department said it had filed a lawsuit to block the sale out of concern that it would give Tribune Publishing “a monopoly over newspaper sales in each county and allow it to increase subscription prices, raise advertising rates and invest less to maintain the quality of its newspapers.”

The deal also is subject to court approval at a hearing scheduled for later this month because the parent company of the two newspapers, Freedom Communications, filed for bankruptcy late last year.

The agreement, if approved, would end a long process for both Tribune Publishing, which has coveted the Southern California newspapers as part of a plan to expand its reach and streamline costs, and Freedom Communications, which initially aimed to revamp the newspaper business in the region but fell victim to the same forces that have besieged newspapers across the country.