The United States has issued a global travel warning following recent terrorist attacks by Islamic militants.
In a statement Friday, the U.S. State Department said kidnappings and hostage events involving U.S. citizens have become increasingly prevalent around the world, and it urged U.S. citizens to main a high level of vigilance.
It said authorities believe there is an increased likelihood of reprisal attacks against Westerners for the U.S.-led military action on Islamic State militants in Syria and Iraq.
The State Department cited Europe as a place where there is growing likelihood of terror attacks as European members of the Islamic State group return from the Middle East.
The travel alert came hours after French police killed three hostage-takers, two of them involved in Wednesday's deadly attack on a satirical magazine in Paris.