(Reuters) - The Swiss city of Geneva raised its alert level on Thursday and said it was looking for suspects who, according to national officials, had possible links to terrorism.
A security guard at the United Nations' European headquarters told Reuters that Swiss authorities were searching for four men believed to be in or near the city.
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Another guard said the U.N. compound was on maximum alert, and Geneva prosecutors said they were investigating the preparation of criminal acts.
Federal police in the capital Berne said they had passed on information about people with possible links to terrorism, but were not connecting them to Islamist militant attacks in Paris last month in which 130 people were killed.
The newspaper Le Matin said a car registered in Belgium, home to some of the Paris attackers, had driven through a police check near Geneva, prompting police to examine a photograph of four suspected Islamist militants provided by the U.S. Central Intelligence Agency (CIA). Two sources confirmed that the CIA had provided the photo, but a CIA spokesman in Washington declined to comment.
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The Tribune de Geneve newspaper said a suspect car with two men in it had been spotted in Geneva, which sits on the French border, and then leaving Switzerland. Swiss television said the city's Jewish community had been told to be vigilant.
"Sensitive sites have been alerted," a Swiss official said.
The guards stationed at vehicle entry points to the U.N. grounds were, unusually, carrying Mp5 sub-machine guns on Thursday. One guard said the U.N. premises had been evacuated for a time late on Wednesday night "as a precaution."
The sprawling complex sits at the heart of "international Geneva." The headquarters of the World Health Organization, the U.N. human rights office, the refugee agency UNHCR, the World Trade Organization and the International Committee of the Red Cross are a short walk away.
%shareLinks-quote="The heightened security affects the entire Geneva area, and the U.N. is taking measures that are commensurate with those taken in the host country" type="quote" author="Rheal LeBlanc" authordesc="U.N. Geneva spokesman" isquoteoftheday="false"%
"The heightened security affects the entire Geneva area, and the U.N. is taking measures that are commensurate with those taken in the host country," U.N. Geneva spokesman Rheal LeBlanc said.
Senior U.S. and Russian diplomats are set to hold talks on Syria in Geneva on Friday, but the United Nations said the location would be kept secret.
Swiss and French officials say they have been working closely together since the Paris attacks. The Swiss Attorney General's office is currently conducting 33 criminal proceedings linked to Islamist militancy, and opened nearly a dozen new investigations in October and November, a spokeswoman said.
The Geneva Department of Security initially said Thursday's measures were "in the framework of investigations carried out following the Paris attacks," until the federal police denied any immediate connection.
(additional reporting by Tom Miles in Geneva and John Miller in Zurich and Mark Hosenball in Washington; Editing by Tom Miles and Kevin Liffey)
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