A total of 158 countries, regions and international organizations have confirmed their participation in the 2010 World Expo to be held in Shanghai, China, by Tuesday.

Yang Xiong, deputy mayor of Shanghai and member of the organizing committee for the World Expo 2010 Shanghai China, told a news conference in Shanghai Tuesday.

The organizing committee forecast that more than 200 countries, regions and international organizations are expected to attend the 184-day event.