A trader passes by the post where Level 3 Communications is traded on the floor of the New York Stock Exchange (NYSE) in New York City. Reuters/Brendan McDermid (Reuters) - Telecommunications provider CenturyLink Inc has won U.S. antitrust approval for its purchase of Level 3 Communications Inc on condition that it sell certain assets, according to a court filing dated on Monday.

CenturyLink agreed to buy Level 3 last year in a deal valued at about $24 billion. It is seeking to expand its reach in the business communications market and compete with rivals such as AT&T and Verizon.

Louisiana-based CenturyLink provides broadband and landline phone services, mainly in rural areas, as well as backhaul, considered the backbone of the internet.

The deal was approved on condition that the companies sell Level 3's telecommunications networks in Albuquerque, Boise, and Tucson. It must also offer long-term leases called indefeasible rights of use for unused fiber optic cable, also called dark fiber, along 30 intercity routes.

The deal, which the companies expected to close in mid- to late-October, is awaiting approval by the Federal Communications Commission and the California Public Utilities Commission, CenturyLink said in a statement.

"We are pleased that the Department of Justice has conditionally cleared CenturyLink's acquisition of Level 3. It is an important milestone in our overall approval process," said CenturyLink Senior Vice President for Public Policy and Government Relations John Jones in a statement. (Reporting by Diane Bartz; Editing by Susan Thomas and Rosalba O'Brien)