US president Barack Obama has spoken of the drastically heightened cyber threat facing nations around the world, as he announced major changes to the American defence strategy.

As he appeared at the Pentagon last week to unveil the new defence strategy, Obama promised to focus closely on improving the technological capabilities of the US armed forces. "We will ensure that our military is agile, flexible and ready for the full range of contingencies," he said.

The US prioritisation of cyber security comes as Israel's deputy foreign minister compared a recent cyber-attack, in which credit card accounts were compromised, to a terrorist act.

The US, in its strategy, said it was stepping up spending on national cyber security, even though it is slashing the overall defence budget and the number of on-the-ground military personnel under the strategy. The cuts in personnel are aimed at achieving $450 billion (£290 billion) in Pentagon savings over the next decade.

The strategy document focused closely on the potentially severe online threats to America.

"Both state and non-state actors possess the capability and intent to conduct cyber espionage and, potentially, cyber attacks on the United States, with possible severe effects on both our military operations and our homeland," said the Sustaining Global Leadership document.

In the document, the Department of Defense warned that "sophisticated adversaries" will use "asymmetric capabilities, to include electronic and cyber warfare, ballistic and cruise missiles, advanced air defenses, mining, and other methods, to complicate our operational calculus".

"Our planning envisages forces that are able to fully deny a capable state's aggressive objectives in one region by conducting a combined arms campaign across all domains - land, air, maritime, space, and cyberspace."

The strategy document also shed light on how highly the Department of Defense also views the importance of establishing a more advanced high tech communications infrastructure for the US forces. "Modern armed forces cannot conduct high-tempo, effective operations without reliable information and communication networks and assured access to cyberspace and space," it said.

Secretary of defense, Leon Panetta, said that even though the US is cutting its overall defence budget, "we will protect, and in some cases increase, our investments in special operations forces, in new technologies like ISR and unmanned systems, in space - and, in particular, in cyberspace".