The U.S issued its warning on Tuesday, saying targets could include the European soccer championship in France, although a State Department official said there was no specific threat information.
The STOXX Europe 600 Travel & Leisure Index <.SXTP> was down 0.8 percent by 0715 GMT, slightly underperforming a 0.5 percent fall on the broader, pan-European STOXX 600 index <.STOXX>.
Shares in airlines such as Air France KLM (>> Air France-KLM), British Airways' owner International Consolidated Airlines Group (>> International Consolidated Airlns Grp SA) and Lufthansa (>> Deutsche Lufthansa AG) all dipped by 0.2-0.5 percent.
Hotels group Accor (>> ACCOR) also fell 1.9 percent, while shares in Aeroports de Paris (>> ADP) were flat.
(Reporting by Sudip Kar-Gupta; editing by Ralph Boulton)
