Sweden and Japan on Monday joined Britain and the United States in warning their citizens about possible terrorist attacks in Europe. The advisories come amid concerns about a possible terror attack by al-Qaida and other groups.
Security was tight in Paris, but some tourists expressed little concern about the latest warnings, including these visitors from Japan and the United States
"Terrorism is not something I think about, really."
"I don't really know anything about terrorists."
"Japan is a peaceful country. We've come to France and heard there's danger here, but it's not something we've seen any evidence of."
"Of course, it is in the back of our mind, but I don't think that it would stop me. I mean I had a wonderful time and I would come back again."
Sweden and Japan are warning their citizens in Europe to be cautious when using public transportation and visiting tourist sites.
Britain's security agency MI5 has upped the threat level from international terrorism in Britain to "severe," indicating a terrorist attack is highly likely.
Britain also warned its citizens of a "high" threat of terror attacks in France and Germany.
However, Germany's Interior Minister said Monday there were no immediate indications of a terrorist attack against his country.
In Washington, U.S. officials repeated travel alerts for Americans already overseas.
White House Spokesman Robert Gibbs.
"This is not a warning, a travel warning telling people not to go," said Robert Gibbs. "This is simply to raise awareness, and alertness of those who are there, to report suspicious activity, be very aware of your surroundings."
State Department spokesman P.J. Crowley said the U.S. has "credible" information to justify the alert. But he said there was not enough specific information to cite individual countries as being at greatest risk.
For days, security officials in Europe and the United States have been discussing the possibility of armed attackers staging an attack in Europe similar to the 2008 assault against Mumbai, India.
166 people died in that attack.
Last week, western intelligence officials said they had uncovered a plot by militants linked to al-Qaida, based in Pakistan, for terror attacks in major British, French and German cities.
U.S. and British news reports quote intelligence officials as saying that some recent missile strikes, targeting militants in Pakistan's northwestern tribal region, were intended to break up that plot.