NEW YORK, July 21: A video of US President George Bush giving a spontaneous back-rub to German Chancellor Angela Merkel at the G8 summit in St Petersburg, Russia, has intrigued and scandalized Americans.

The five-second video and series of photographs, recently posted on YouTube.com and various blogs, show Mr Bush surprising Ms Merkel by hurriedly rubbing the back of her neck and shoulders.

The chancellor immediately hunches her shoulders, throws her arms up and grimaces, though she appears to smile as Mr Bush walks away.

The video is these days one of the most popular clips on the Web, spawning countless remarks on etiquette for world leaders.

Coupled with Mr Bush’s use of an expletive at the summit and a US senator comparing the Internet to a ‘series of tubes, the incident reveals anew the power of the Web - and YouTube, specifically — to beam embarrassing political gaffes around the world.

Larry Sabato, professor of politics at the University of Virginia, told reporters that today public figures have to be more careful in ‘a thousand ways.

But he maintains sites like YouTube can be revealing. “If they’re not doing something that’s embarrassing, they have nothing to worry about,” he says.

“A president ought to know enough not to use an expletive in a fairly open meeting and almost any male alive today knows that you don’t offer uninvited massages to any female, much less the chancellor of Germany.”

Many writers saw a sexist aspect to Mr Bush’s back rub. “This isn’t a Sigma Chi kegger, it’s the G8 summit,” wrote blogger Christy Hardin Smith on Firedoglake.com.