Story highlights The State Department has issued a worldwide travel alert warning Americans of terror attacks

State warned of terror groups' plots as well as individuals carrying out their own attacks

Washington (CNN) The United States issued a worldwide travel alert for Americans amid concerns that terror groups and individuals plan more attacks after the Paris massacres.

The State Department warned that groups like ISIS, al-Qaeda and Boko Haram "continue to plan terrorist attacks in multiple regions."

It also warned of the possibility of individuals carrying out their own attacks.

"These attacks may employ a wide variety of tactics, using conventional and non-conventional weapons and targeting both official and private interests," the department said in issuing a travel alert that expires on February 24, 2016.

The alert does not instruct Americans to avoid travel, but it does urge U.S. citizens to "exercise vigilance when in public places or using transportation."

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