French anti-terrorist police arrested six men on charges of belonging to a radical Islamist group and preparing attacks in France, local media reported on Tuesday. \"The dismantled group is a very serious cell\" that prepared \"terrorists attacks\" in the French territory, the news channel BFMTV quoted a source close to the investigation as saying. Aged between 22 and 38, the suspects arrested on Monday in the Paris Region were all known to police for various offences. In April, they were suspected of robbing La Banque Postale branch in Seine-et-Marne, during which the agency director and his wife had been abducted and sequestered. \"They apparently planned to commit more robberies\" to finance their terror projects, the source added. The group composed of four French nationals, a Benin national and a Comoros could be placed under formal investigation after their questioning that could last up to 96 hours. France has reinforced its security measures since January, when its forces intervened in Mali to help local authorities to repel al-Qaida-linked Islamist rebels who had seized control of the north of the former French colony. A total of seven French nationals are now in hands of al-Qaida-linked groups in the Sahel region.