North Korea today began expelling staff and shutting South Korean-owned buildings at a mountain resort in retaliation for Seoul's ban on cross-border tours. The South's unification ministry said the North used stickers to seal five Seoul-owned buildings at the Mount Kumgang resort. A ministry spokesman said four Korean-Chinese employed by South Korea were told to leave within 24 hours. He said a family reunion centre, a fire station, a cultural centre, a spa and a duty-free shop were sealed off. The tours, which once earned the impoverished North tens of millions of dollars a year, were suspended in July 2008 after North Korean soldiers shot dead a South Korean housewife who had strayed into a military zone. The sanctions-hit North Korea has been pushing to revive the business.<br/>