CBS Corp (CBS) and Time Warner Inc.'s (TW) Warner Brothers television network said Tuesday that they will close their respective UPN and WB networks and jointly launch the CW network.

The announcement was made by exectives from CBS, which owns UPN, and Warner Bros., which owns WB.

Both UPN and WB had struggled to compete against larger rivals in the broadcast TV business, including Walt Disney Co.'s (DIS) ABC, News Corp.'s (NWS) Fox and CBS Corp.'s CBS. News Corp. is the parent company of the Fox News Channel, which operates FOXNews.com.

The new network will launch in the fall, the executives said, and both UPN and WB will shut down. It will be a 50-50 partnership between Warner Bros. and CBS, and the network will be carried on stations owned by the Tribune Co. (TRB), which is a minority owner of the WB network.

Leslie Moonves, chief executive of CBS Corp., said the new network will air 30 hours of programming seven days a week aimed in part at young audiences.

Moonves billed the CW as a "fifth network."

The companies expect the station to reach 95 percent of the country.

Tribune said its 16 UPN broadcast stations signed 10-year affiliate agreements with the new network. Similarly, CBS said its 12 UPN stations signed 10-year affiliate deals. The two station groups reach 48 percent of the country. The companies expect the remainder of the affiliates to come from a combination of WB and UPN stations.

The CW will use The WB's current scheduling model, which consists of Monday through Friday nights from 8-10 p.m. EST; Sundays from 7-10 p.m. EST; Sunday from 5-7 p.m. EST outside of primetime. It will also include a Monday through Friday afternoon block from 3-5 p.m. EST and a 5-hour Saturday morning animation block.

Barry Meyer, the head of Warner Bros., said the network would be run by the current executives of UPN and WB.

Reuters and the Associated Press contributed to this report.