Sprint's LTE network will light up in Atlanta, Dallas, Houston, San Antonio and Kansas City, Kan., on July 15, the first five markets of its planned 10-city launch.

The Wednesday announcement left out any mention of a launch in Baltimore, one of the LTE markets Sprint named in February.

"We expect to have news on the launch of 4G LTE in Baltimore soon," a Sprint spokesman said, but he did not provide a reason why the start of LTE service in Maryland had been delayed.

More markets will be named later this year, Sprint said. The LTE build-out is expected to be largely complete by the end of 2013.

CEO Dan Hesse said at a January investor conference that Atlanta and the three Texas metropolitan areas would be part of a mid-year LTE rollout spanning 10 markets. Baltimore and Kansas City, Kan., were named as LTE cities the following month.

About 250 employees were recently transferred back to Sprint from Ericsson to assist with the company's network overhaul, according to widespread reports. The increase in staffing raised investor concerns about possible complications with the major project, which is simultaneously rolling out LTE, re-farming spectrum, decommissioning Sprint's iDEN network and replacing it with a CDMA-based push-to-talk service.

Sprint needs the LTE service to compete effectively with AT&T and Verizon Wireless, which already have their LTE networks up and running. AT&T's LTE service is available in about 40 markets, a fraction of the more than 300 markets covered by Verizon's next-generation mobile broadband network.

The first LTE smartphones for Sprint's new network launched in April, three months before the service is expected to go live. The operator currently offers five LTE devices, including the Samsung Galaxy S III.