The South Koreans arrived ahead of the event this weekend on tourist visas despite their government's recommendation against their visit and some attempts to stop them at the borders, embassy and Western officials said.

The South Korean embassy in Kabul has suggested the roughly 200 South Koreans who live in Afghanistan, most of them in the capital, take their holidays abroad until the event is over, an embassy official told AFP.

"Most of them have followed our recommendation -- I've been getting reports that the majority have already left," the official said on condition of anonymity.

"We are very concerned about our own nationals' security. We have given so many warnings to the organisers but they have made their own decision."