PARIS â€” Police were reported on Wednesday to have detained 10 suspected Islamic militants in early-morning raids across France â€” the latest in a series of measures apparently designed to display a forceful response to the killing of three Jewish schoolchildren, a rabbi and three French soldiers in the southwest of the country last month. The round-up, with police officers and domestic security agents raiding at least five locations as far apart as Marseille in the south and Roubaix in the north, came 18 days before the first round of French presidential elections in which law-and-order issues have assumed prominence since the March attacks in Toulouse and Montauban. â€œIf there are suspicions, if there are risks, then they must be acted upon,â€ the Socialist candidate, FranÃ§ois Hollande, who is leading President Nicolas Sarkozy in opinion polls, said in a radio interview on Wednesday. â€œBut what might be surprising is why do it after an act of terrorism which has, it is true, deeply affected our spirits? â€œI am not questioning what is being done. All I am saying, simply, is that we should have perhaps done more beforehand.â€ News report quoted unidentified police sources as saying the 10 people arrested were suspected of either planning to travel to or returning from Afghanistan or Pakistan for training. The 10 were said to be individuals rather than an organized network and to have the same disaffected, lonerâ€™s profile as the Mohammed Merah, the 23-year-old gunman who claimed to have ties to Al Qaeda and who was shot to death by police after last monthâ€™s killings in the southwest. The latest arrests came a day after a state prosecutor said judicial authorities will indict 13 Muslim radicals suspected of plotting terrorist acts in France, though he acknowledged that any plans of violence by them had remained at an â€œintellectualâ€ stage, including a plot to kidnap a magistrate in Lyon. The 13 individuals, members of the Islamist group Forsane Alizza, or Knights of Pride, were arrested in raids across the country on Friday. Investigators recovered three Kalashnikov assault rifles in the suspectsâ€™ possession, along with several handguns, according to FranÃ§ois Molins, the prosecutor. Members of the group had in recent months participated in â€œphysical trainingâ€ in public parks and forests near Paris, Mr. Molins said, and had undergone â€œreligious indoctrination.â€ He declined to offer further details. News reports quoted police officials as saying the arrests on Wednesday were not part of the same investigation.