A spokeswoman for the artist, Jo Brooks, said: "The Israeli security forces did shoot in the air threateningly and there were quite a few guns pointed at him. The images are still there."

The barrier, made of concrete walls and razor-wire fences, has been declared illegal by the UN, which has ordered it to be dismantled. This is not the first of Banksy's stunts. He once placed a painting of a can of Tesco tomato soup and a woman wearing a gas mask in New York galleries.

And earlier this year, staff at the British Museum in London were left with red faces after discovering one of his hoax exhibits on display - a cave painting of a primitive man pushing a supermarket trolley. The "rock painting", entitled Early Man Goes to Market, depicted the outline of a spear-wielding caveman pushing a trolley, but failed to raise eyebrows among staff at the museum for several days.