The U.S. Department of Justice is seeking additional information related to Broomfield-based Level 3 Communications Inc.'s acquisition of Global Crossing Ltd., the two companies announced Tuesday morning. 

The two firms received a “second request” letter from the Justice Department under the Hart-Scott-Rodino Act, which allows the Federal Trade Commission and the Department of Justice to review certain proposed mergers and acquisitions and determine if they would violate antitrust laws.

Both firms, in their respective announcements, said they expect the $3 billion transaction — which was announced in April and includes the assumption of $1.1 billion in debt — to close as planned before the end of 2011.

Shares of Level 3 (Nasdaq: LVLT) and Florham, N.J.-based Global Crossing (Nasdaq: GLBC) were down slightly in morning trading.