NSA chief to step down, but not because of PRISM leaks

NSA chief Army General Keith Alexander is set to step down months after it was revealed the agency eavesdrops on the internet and telephone data of civilians without consent.

Alexander, who took charge in 2005, will leave by April 2014, sources have told Reuters. He will also be replaced as the Commander of the US Cyber Command military unit.

Alexander was the chief proponent of data collection initiating the PRISM surveillance program in 2007. He also publicly defended the NSA's activities after former contractor Edward Snowden blew the whistle, claiming they are lawful and necessary to detect and disrupt terrorist activities.

NSA spokeswoman Vanee Vines said Alexander's decision to step down had nothing to do with the information leaked by Snowden.

"This has nothing to do with media leaks, the decision for his retirement was made prior; an agreement was made with the (Secretary of Defence) and the Chairman for one more year - to March 2014," Vines told Reuters in an email.

However, all has not been as rosy at the NSA under Alexander's watch. Tensions have been reported because the chief allegedly wanted to collect as much data as possible and he has also been labelled a "cowboy".

Vice Admiral Michael Rogers, who commands the US Navy's 10th Fleet and US Fleet Cyber Command, is tipped to be made chief of the NSA. He is based in Fort Meade, Maryland, where the NSA is headquartered.