The US has begun waging cyber warfare against Isis, defence secretary Ashton Carter has confirmed.

As the Financial Times reports, Carter said he has issued orders to the US Cyber Command to launch online attacks against the fundamentalist group.

Speaking to the paper, he said: "I have given Cyber Command really its first wartime assignment...and we're seeing how that works out."

He added: "Even a few years ago, it would not have occcured to a Secretary of Defence to say, 'let's get cyber in the game', but here we have real opportunities."

Carter told reporters in February that the Cyber Command, which was formed in 2009, was "looking to accelerate" its digital attacks against Isis, in an effort to disrupt their communications systems, data security and financial structures. Now, it appears the cyber war is being stepped up.

The US has only vaguely alluded to its cyber warfare operations in the past, but Carter's comments are some of the most explicit confirmations so far that the US is deploying digital attacks against its enemies.

"I have given Cyber Command its first wartime assignment" <p>Ashton Carter, US Secretary of Defence</p>

Lifting the veil of secrecy which covers the Cyber Command, headquartered at Fort Meade in Maryland, has been seen as an attempt by the Department of Defence to deter foreign countries from hitting the US with cyberattacks.

Thousands of people have been recruited to the Cyber Command in the last few years, mirroring the expansion of the UK's own digital defence force.