Geneva has been put on security alert, and officials are searching for four terror suspects known from investigations related to the Paris attacks. Though it is not yet known if the men can be directly linked to the attacks in Paris, there is sufficient evidence to believe that they have links to terrorism, reported Reuters.

"In the framework of investigations carried out following the Paris attacks, at the international and national level, Geneva police and their partners are actively looking for people whose description has been provided by the Swiss Confederation," said the Geneva Department of Security in a statement, reported CNBC.

A Belgian-registered car drove through a police checkpoint near Geneva on Dec. 10, and this prompted police to refer to a photo of four suspected Islamist militants provided by the CIA, according to Reuters.

The Geneva Department of Security also noted that they "have increased their level of vigilance and reinforced the number of police agents on the ground," according to RT. Security officials had also seen two other terrorism suspects, not from the CIA photo, in Geneva.

According to a security guard at the U.N. compound in Geneva, the headquarters is on "maximum alert." In a highly unusual measure, guards stand armed with MP5 sub-machine guns at the U.N.'s entry points for cars. The headquarters are located near the French border, reported Politico.