ISLAMABAD, June 22 (Reuters) - About 40,000 Pakistanis are on the move even before a military offensive begins in the Taliban stronghold of South Waziristan, U.N. officials said on Monday, and are headed for communities already stretched to the limit.

Nearly 2 million people have fled fighting in northwest Pakistan, most since early May when the military began an offensive against Taliban insurgents, prompting the United Nations to launch an appeal for $543 million in aid to avert a long-term humanitarian crisis. Full article.