Washington (CNN) -- The State Department is warning Americans that al Qaeda and affiliated organizations continue to plan terrorist attacks against U.S. interests around the world, including Europe, Asia, Africa, and the Middle East.
"These attacks may employ a wide variety of tactics including suicide operations, assassinations, kidnappings, hijackings, and bombings," the department said in its latest Worldwide Caution report, issued Tuesday.
There is an "enhanced potential" for more anti-American violence around the world, it says, in the wake of Osama bin Laden's killing by U.S. special forces in May.
Extremists, the warning says, may use "conventional or non-conventional weapons" and target both official and private interests. It points to targets like "high-profile sporting events, residential areas, business offices, hotels, clubs, restaurants, places of worship, schools, public areas, and other tourist destinations both in the United States and abroad where U.S. citizens gather in large numbers, including during holidays."
The so-called "Arab Spring" movements in the Middle East and North Africa, meanwhile, have resulted in civil unrest and large-scale protests and the State Department warns that even "peaceful" demonstrations can turn violent, that riots can occur "with little or no warning."
A number of al Qaeda-affiliated groups and other extremists continue to operate in and around Africa, the State Department says, and it notes increased threats across East Africa.
Groups like al-Shabaab, al Qaeda in the Lands of the Islamic Maghreb (AQIM) and Taliban elements like Lashkar-e-Tayyiba pose a threat to U.S. citizens as well, the department said in its report, the latest update since a similar warning was posted in January.
U.S. citizens considering travel by sea near the Horn of Africa or in the Southern Red Sea "should exercise extreme caution," it says, as there has been a notable increase in armed attacks, robberies and kidnappings for ransom by pirates.
In Pakistan, extremist groups continue to target U.S. and other Western citizens and interests as well as Pakistani government and military and law enforcement personnel.
The State Department urges U.S. citizens living overseas or planning to travel abroad to enroll in its Smart Traveler Enrollment Program (STEP), which provides updates on safety and security and makes it easier for the U.S. Embassy to contact them in emergencies.