There has been much talk as to how the current tensions among countries around the world could spark a third World War: the deteriorating relationship between the United States and Russia over issues such as the Ukranian crisis and the Syrian civil war, the differences among major countries and Iran over nuclear arms, or the brewing tension between America and China to gain supremacy over the South China Sea.

Cybersecurity expert John McAfee, however, warned that the next war among nations may not be fought with actual arms or soldiers. For him, the war may erupt online, and worse, the Islamic State (ISIS) jihadist group, which has established a caliphate in parts of Syria and Iraq, is capable of winning it.

In an opinion article for the International Business Times, McAfee, who developed the first commercial anti-virus programme, predicted that "the next major war will be a cyberwar."

McAfee said in case this scenario happens, the United States is "woefully unprepared" and even "defenceless."

"In terms of instruments of slaughter, the United States may well be the best-prepared nation in the world. Our arsenal of bullets, bombs, tanks, planes, boats, missiles and our nuclear capabilities are rivalled by few, and likely exceeded by none. None of this matters in a cyberwar – a fact that could damage us when our weapons and equipment are turned against us using computers," the security expert said.

He even went on to say that the ISIS, a terrorist organisation, is more prepared for such a kind of war than the U.S.

"Islamic State may pay lip service to a medieval lifestyle, but they have no difficulty using encrypted social media tools like Twitter to communicate and recruit new members," McAfee said.

He added that China and Russia also are more equipped for cyberwarfare, because they "have massive programmes devoted to weaponised computing."

McAfee urged the U.S. to start protecting its networks to prepare for the possibility of a cyber warfare.

"If we are unable to protect our networks, everything connected to them can be infiltrated by hackers. In our modern world this includes our power grid, nuclear power stations, planes, cars and our entire financial infrastructure. These will be the weapons of cyberwar – turned against us in a perversion of their intended purpose. We are living in a doomsday machine of our own design – one that when activated will make the Battle of Antietam look like a Sunday picnic," he said.