(Recasts to broaden impact, adds U.S. travel warning, details from U.S. travel groups, stock declines, previous LONDON)

By Alwyn Scott

Nov 24 (Reuters) - Heightened travel risks stemming from the recent militant attacks in Paris have depressed flight bookings to the French capital and other destinations, sending travel stocks lower as fears grow of a lengthy slump.

Adding to the concern, the U.S. State Department issued a global travel alert on Monday warning that Islamic State, al Qaeda, Boko Haram and other groups "continue to plan terrorist attacks," and urging citizens to "exercise particular caution during the holiday season and at holiday festivals and events."

New flight bookings to Paris, one of the world's most-visited cities, fell 27 percent in the Nov. 14-21 period from a year ago, travel information firm ForwardKeys said on Tuesday.

The decline followed coordinated attacks in Paris on Nov. 13 that killed 130 people. Cancellations came mostly from leisure travelers rather than those traveling on business or visiting family and friends, said ForwardKeys, which processes data from 14 million global flight reservations a day.

Other groups reported cancellations by tour operators and efforts by some wealthy Chinese tourists to avoid Paris.

"People are shifting their destinations away from Paris and France to other locations in Europe, such as Germany, that are viewed as under less threat," said Paul Hudson, president of FlyersRights.Org, a U.S. consumer advocacy group with 60,000 members.

Low-cost carrier easyJet said on Tuesday it had seen a "cooling off" in demand for travel to France.

Air France has experienced some reduction in traffic following the attacks, but it was too early to quantify, a company source said last week.

Airline and travel stocks fell sharply on Tuesday. Air France was down 3.9 percent and easyjet down 3.2 percent.

On Wall Street, United Continental Holdings Inc was down 3.2 percent at $56.66, Delta Air Lines Inc was down 3 percent at $47.25 and American Airlines was down 2.1 percent at $41.41. Expedia.com was down 2.8 percent at $121.49 and Priceline Group was off 2.6 percent at $1,232.06.

ForwardKeys said bookings for the Christmas period were trailing last year's level by 13 percent. It said cancellations spiked 21 percent in the week after the Paris attacks, compared with the same period last year.

In recent days, the level of cancellations had stabilized at about the same level as last year as airlines stopped offering free rebooking, it added.

But "booking trends are not yet showing signs of recovery," ForwardKeys Chief Executive Olivier Jager said in an interview. "It's going to take many months."

(Reporting by Sarah Young in London, Alwyn Scott in Seattle and Katie Reilly in New York; Editing by Ruth Pitchford and Peter Cooney) ((alwyn.scott@thomsonreuters.com; +1-646-223-6132; Reuters Messaging: alwyn.scott.thomsonreuters.com@reuters.net))

Keywords: FRANCE SHOOTING/TRAVEL