US issues global travel alert in wake of Paris attacks

The United States issued a worldwide travel alert on Monday ahead of the Thanksgiving holiday, warning American citizens of "increased terrorist threats" in the wake of the Paris attacks.

A massive manhunt is underway in France and Belgium for Belgian-born Salah Abdeslam, suspected of playing a role in the coordinated shooting and suicide bombings of 13 November claimed by the Islamic State (IS) group.

The United States has been on heightened alert in the wake of the attacks, which killed 130 people.

"Current information suggests that ISIL (aka Daesh), Al-Qaeda, Boko Haram and other terrorist groups continue to plan terrorist attacks in multiple regions," said a State Department travel advisory, using alternate names for IS.

"US citizens should exercise vigilance when in public places or using transportation," it said, advising Americans to avoid large crowds or crowded places and to "exercise particular caution during the holiday season".

Citing recent attacks in Denmark, France, Mali, Nigeria and Turkey, it also noted the threat of "lone wolf" attacks by unaffiliated persons inspired by terror groups.

The alert, which expires 24 February, warned that "the likelihood of terror attacks will continue as members of ISIL/Daesh return from Syria and Iraq".

It was referring to foreign fighters who return home after having fought alongside IS extremists.

"Extremists have targeted large sporting events, theaters, open markets and aviation services," the alert added.

The State Department often issues individual country travel alerts, but this notice was a rare "worldwide travel alert" that comes in the wake of a series of attacks.

New "attacks may employ a wide variety of tactics, using conventional and non-conventional weapons and targeting both official and private interests," it said, recommending that travelers "monitor media and local information sources and factor updated information into personal travel plans and activities".

The warning went on to say that "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."

Former FBI assistant director Tom Fuentes was quick to downplay the travel alert on CNN, saying the warning was nothing new.

"It's the same thing they're always putting out," Fuentes said. "Americans need to be vigilant anywhere they're going in the world. These (attacks) are always possible. They've been possible for a long time now."

Former CIA official Philip Mudd concurred. "There are officials in government responsible for dissemination these kinds of warnings. This is a classic warning from a bureaucratic group that does this. To my mind if you're a traveler today and you didn't know that it might be dangerous to go to Brussels or Paris, you're not watching the TV."