French police have smashed a neo-Nazi cell accused of plotting attacks on places of worship that has fueled safety concerns in Europe's largest Muslim community.

Five members of the group, who were "close in ideology to the neo-Nazi movement" were charged between September and May over the alleged plot, a source close to the investigation said. "The investigation suggested they were developing an ill-defined plot to carry out an attack, likely to target a place of worship," the judicial source said.

Police in the southeastern city of Grenoble first arrested a man on weapons charges in September 2018. The investigation led them to the four other suspects, two of them minors. Anti-terrorism investigators took over the investigation in January and charged the suspects with terror offences, including making and transporting explosive devices and being part of a terrorist conspiracy.

France remains on high alert following a wave of militant attacks which have killed more than 240 people since 2015. Officials have urged people not to confuse the actions of radicalized individuals with those of France's estimated six million Muslims, but anti-Islamic violence is on the rise. A handful of alleged plots involving far-right extremists have made headlines in recent months. In June 2018, 13 people with links to the radical Action des Forces Operationnelles (Operational Forces Action) group were arrested by anti-terrorist police over an alleged plot to attack Muslims. The Guerre de France (War for France) website of the shadowy radical group depicted an apocalyptic battle scene under the Eiffel Tower, and claims to prepare "French citizen-soldiers for combat on national territory." France's TF1 television said the group planned to target radicalized imams after their release from jail, as well as veiled women in the street chosen at random. France registered 72 violent anti-Muslim acts in 2017, up from 67 in 2016. In July 2017, a 23-year-old was charged with plotting to assassinate the president at France's Bastille Day military parade. The man told investigators he wanted to kill President Emmanuel Macron along with "Muslims, Jews, blacks and homosexuals," and three kitchen knives were found in his car.