US-based AT&T has won a $74.6m telecom services contract from the US Department of Defense's (DoD) Defense Information Systems Agency (DISA).
The five-year contract requires AT&T to provide secure telecom services for senior leadership communications between DoD aircraft and ground stations worldwide.
AT&T global business public sector solutions president Kay Kapoor said: "We're proud to provide communications services to help defend our country.
"When the mission is vital and national security is at stake, our nation's leaders count on the AT&T network."
The company will provide long-haul telecommunications and transmission circuits to support the government's restricted-use, ultra-high-frequency communications platform.
DISA comprises nearly 6,000 civilian employees, more than 1,500 military personnel, and approximately 7,500 defence contractors.
The agency provides command and control and information-sharing capabilities, as well as infrastructure to support warfighters, national leaders, and other mission and coalition partners during military operations.
DISA is currently working with the National Security Agency (NSA), the Department of Defense Chief Information Officer (DoD CIO) and US Cyber Command to evaluate cyber-security solutions for DoD's network.