The staff numbers at US Cyber Command planned to be increased from 900 to 4,900.
The US Defense Department is planning to expand its cyber-security team in a bid to counter threats against government computer networks.
Under the plan, the US Cyber Command, will be expanded over the coming few years.
The move follows a warning from US defence secretary, Leon Panetta, who said the country could face a 'cyber-Pearl Harbor' and has drafted new rules which would enable military to move quickly to thwart such attacks.
Panetta warned that digital attacks from foreign soils could paralyse the country's financial networks and transportation system.
According to the Washington Post, the Cyber Command, which currently employs 900 members including both military and civilian, has secured an approval to increase it's number to 4,900 troops and civilians.
Reports suggest that the plan will create three types of forces under the Cyber Command. This includes 'national mission forces' to guard computer systems that involve electrical grids and other infrastructure; 'combat mission forces' which will have a moreproactive role in cyberwarfare, planning and executing cyber operations; and 'cyber protection forces' to protect internal systems of the Defense Department.