Geneva (dpa) - Geneva was on alert Thursday following reports that terrorists might be planning attacks in and around the city, which is home to the second largest site of the United Nations, a spokesman of the Swiss police said.Officers were searching for several people suspected of having links with the terrorist attacks in Paris on November 13, according to the spokesman.The suspects were believed to be either in or near Geneva, and police were working with national and international bodies in the search.Police were focused on high-risk locations such as the buildings of international organizations, the airport, the train station and synagogues.Formal legal proceedings had been set in motion against the terrorist suspects, the federal public prosecution service said in the capital Bern. All available information had been passed on to the security forces in Geneva, which is located on the border to France.According to unconfirmed Swiss media reports, police were looking for five suspects after a tip-off from the US Central Intelligence Agency (CIA) that attacks might have been planned. The daily Le Matin reported that one of the suspects had been arrested.Suspicions had been raised by an internet video showing four bearded men who might have connections to the Islamic State extremist group. The fifth suspect is said to have threatened attacks in Geneva and in the Canadian cities of Vancouver and Ottawa, according to Le Matin.Police, citing the ongoing investigation, declined to go into deeper detail about the suspects or their connection to the Paris attacks.They also did not confirm local media reports that the investigation was related to talks between high-ranking US and Russian officials scheduled for Friday on the conflict in Syria.The planned talks were to prepare further peace negotiations in Syria, a UN spokesman said. However, the talks would not take part at the UN site in Geneva, but at another undisclosed location.Russian Vice Foreign Minister Gennadi Gatilov was among those due to attend, Russian news agency RIA Novosti reported earlier.Already several days ago security personnel and checks had been upped at the various entrances to the UN site, UN diplomats said. According to witnesses several of the UN security personnel had been carrying automatic guns, which usually only happened in high-risk situations.A vague threat had turned into a concrete one, Emmanuelle Lo Verso, the spokeswoman for the Geneva security department said without giving any further details. The department had received descriptions of several people considered as dangerous as well as the description of a car.Swiss border police in the Geneva region were also on heightened alert. The surveillance web was very close-knit, the media spokesman for the border force, Michel Bachar, told Swiss news agency sda.