WASHINGTON, Dec. 20 (UPI) -- The U.S. Department of State issued a worldwide travel alert in response to the attack in Sydney this week, warning "terrorist groups and those inspired by them can pose unpredictable threats in public venues."
The attack on Monday that left two hostages dead should serve as a reminder that United States citizens must be extra vigilant during holiday travel abroad, the State Department said. Intelligence officials said there are no specific threats against Americans traveling abroad, but are concerned about similar attacks.