US:A ray gun that shoots a beam which makes people feel as if they will catch fire has been unveiled by the US military.
The technology is supposed to be harmless - a non-lethal way to get enemies to drop their weapons.
Military officials say it could save the lives of innocent civilians and service members in places such as Iraq and Afghanistan.
During the first media demonstration of the weapon at Moody Air Force base, in Georgia, airmen fired beams from a large dish antenna mounted on a Humvee at people pretending to be rioters.
The crew fired beams from more than 460m (500 yards) away, nearly 17 times the range of existing non-lethal weapons such as rubber bullets.
While the sudden 54-degree heat is not painful, it is intense enough to make participants think their clothes are about to ignite.
"This is one of the key technologies for the future," said Marine Col Kirk Hymes.
The system uses millimetre waves, which can penetrate the skin just enough to cause discomfort.
By comparison, common kitchen microwaves can penetrate several centimetres of flesh.
The millimetre waves cannot go through walls, but they can penetrate most clothing, officials said.
They refused to comment on whether the waves can go through glass.