Increasingly autonomous, gun-toting robots developed for warfare could easily fall into the hands of terrorists and may one day unleash a robot arms race, a top expert on artificial intelligence says.

"They pose a threat to humanity," University of Sheffield professor Noel Sharkey said, ahead of a keynote address before Britain's Royal United Services Institute.

Intelligent machines deployed on battlefields around the world - from mobile grenade launchers to rocket-firing drones - can already identify and lock onto targets without human help.

There are more than 4,000 US military robots on the ground in Iraq, as well as unmanned aircraft that have clocked hundreds of thousands of flight hours.

The first three armed combat robots fitted with large-calibre machine guns deployed to Iraq last summer, manufactured by US arms maker Foster-Miller, proved so successful that 80 more are on order, Professor Sharkey said.

But up to now, a human hand has always been required to push the button or pull the trigger.

It we are not careful, he said, that could change.

"[Military leaders] are quite clear that they want autonomous robots as soon as possible, because they are more cost-effective and give a risk-free war," he said.

Several countries, led by the United States, have already invested heavily in robot warriors developed for use on the battlefield.

South Korea and Israel both deploy armed robot border guards, while China, India, Russia and Britain have all increased the use of military robots.

The US Government plans to spend $4.28 billion by 2010 on unmanned technology systems, with total spending expected rise to $25.7 billion, according to the Department of Defence's Unmanned Systems Roadmap 2007-2032, released in December.

Human-robot ratio

James Canton, an expert on technology innovation and chief executive of the Institute for Global Futures, predicts that deployment within a decade of detachments that will include 150 soldiers and 2,000 robots.

The use of such devices by terrorists should be a serious concern, Professor Sharkey said.

Captured robots would not be difficult to reverse engineer, and could easily replace suicide bombers as the weapon-of-choice.

"I don't know why that has not happened already," he said.

But even more worrisome, he continued, is the subtle progression from the semi-autonomous military robots deployed today to fully independent killing machines.

"I have worked in artificial intelligence for decades, and the idea of a robot making decisions about human termination terrifies me," he said.

- AFP