French police officers patrol near the Eiffel Tower, in Paris, Monday Nov. 23. French President Francois Hollande will preside over a national ceremony on Nov. 27 honoring the at least 130 victims of the deadliest attacks on France in decades. (AP Photo/Jacques Brinon)



Americans should be alert to the possible travel risks, especially during the holidays, following increased terrorist threats around the world, the State Department warned on Monday.

A travel alert, which is to be in effect until Feb. 24, said current information suggests that militants with the Islamic State, al-Qaida, Boko Haram and other terrorist groups continue to plan attacks in multiple regions. U.S. authorities said the likelihood of terror attacks will continue as members of IS return from Syria and Iraq, and other individuals not affiliated with terror groups engage in violence on their own.

Related: Amid Global Terror Threat: Where is it Safe to Travel Right Now?

Empty tables are seen at a restaurant on the Grand Place in Brussels, Monday, Nov. 23. The Belgian capital Brussels has entered its third day of lockdown, with schools and underground transport shut and more than 1,000 security personnel deployed across the country. (AP Photo/Alastair Grant)

Extremists have targeted sporting events, theaters, open markets and aviation targets. In the past year, there have been multiple attacks in France, Nigeria, Denmark, Lebanon, Turkey and Mali. IS has claimed responsibility for the Oct. 31 bombing of a Russian airliner in Egypt, killing 224 people.



Related: Take That, Terrorism! 7 Ways to Travel Without Fear



“U.S. citizens should exercise vigilance when in public places or using transportation,” the alert said. “Be aware of immediate surroundings and avoid large crowds or crowded places. Exercise particular caution during the holiday season and at holiday festivals or events.”

The State Department said the U.S. is exchanging information with allies about threats of international terrorism.

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The travel alert was issued the same day that Belgium’s prime minister announced that Brussels would remain at the highest alert level for at least another week. The increased security measures following the Nov. 13 attacks in Paris that killed 130 people have virtually shut down the Belgian capital.

Related: How to Travel Abroad Safely in the Age of Terrorism

A Belgian Army soldier patrols a main shopping street in Brussels. (AP Photo/Thierry Monasse)



The statement issued Monday said:



Current information suggests that ISIL (aka Da'esh), al-Qa'ida, Boko Haram, and other terrorist groups continue to plan terrorist attacks in multiple regions. These attacks may employ a wide variety of tactics, using conventional and non-conventional weapons and targeting both official and private interests. This Travel Alert expires on February 24, 2016.



Authorities believe the likelihood of terror attacks will continue as members of ISIL/Da'esh return from Syria and Iraq. Additionally, there is a continuing threat from unaffiliated persons planning attacks inspired by major terrorist organizations but conducted on an individual basis. Extremists have targeted large sporting events, theatres, open markets, and aviation services. In the past year, there have been multiple attacks in France, Nigeria, Denmark, Turkey, and Mali. ISIL/Da'esh has claimed responsibility for the bombing of a Russian airliner in Egypt.



U.S. citizens should exercise vigilance when in public places or using transportation. Be aware of immediate surroundings and avoid large crowds or crowed places. Exercise particular caution during the holiday season and at holiday festivals or events. U.S. citizens should monitor media and local information sources and factor updated information into personal travel plans and activities. Persons with specific safety concerns should contact local law enforcement authorities who are responsible for the safety and security of all visitors to their host country. U.S. citizens should:

• Follow the instructions of local authorities. Monitor media and local information sources and factor updated information into personal travel plans and activities.

• Be prepared for additional security screening and unexpected disruptions.

• Stay in touch with your family members and ensure they know how to reach you in the event of an emergency.

• Register in our Smart Traveler Enrollment Program (STEP).

Foreign governments have taken action to guard against terrorist attacks, and some have made official declarations regarding heightened threat conditions. Authorities continue to conduct raids and disrupt terror plots. We continue to work closely with our allies on the threat from international terrorism. Information is routinely shared between the United States and our key partners in order to disrupt terrorist plotting, identify and take action against potential operatives, and strengthen our defenses against potential threats.

WATCH: What ‘Suspicious Behavior’ Should You Report in the Age of Terrorism?

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