Terrorists or agents of hostile powers could mount attacks on companies and systems that control vital parts of an economy, including power stations, electrical grids, and communications networks.
The Tunisian military has sent reinforcements and helicopters to the area, and authorities have been hunting several attackers who were still at large.
European health experts have said other European countries should see the severe flu hitting Britain at the moment as a warning of what might be coming to them soon.
Death toll from Typhoon Haiyan in the Philippines rose to 3,637, after the strongest storm this year destroyed the central part of the country on Nov. 8, 2013.