The Worldwide Caution updates information issued Jan. 31 on the threat terrorist actions and violence pose to U.S. citizens and interests throughout the world, the department said in a statement.
The State Department said it believes there remains a high potential for anti-American violence since the death of al-Qaida founder Osama bin Laden in May. Current information suggests al-Qaida and affiliated organizations still plot terrorist attacks against U.S. interests in many regions, including Europe, Asia, Africa and the Middle East, the department said.
The department said U.S. citizens should be aware of potential terrorist attacks on public transportation systems and other tourist infrastructure.
Because of the protests that have swept across northern Africa and the Middle East since spring, the State Department warned U.S. citizens in those regions to be alert for the potential for violence and avoid areas of demonstrations if possible.
"U.S. citizens are warned that demonstrations intended to be peaceful can escalate into violent clashes," the statement said. "U.S. citizens are reminded that demonstrations and riots can occur with little or no warning."
The department also warned about taking "extreme caution" when traveling by sea near the Horn of Africa or in the southern Red Sea "as there has been a notable increase in armed attacks, robberies and kidnappings for ransom by pirates."