France's anti-terrorism prosecutors said Tuesday that they had opened an inquiry after a man claiming allegiance to the Islamic State group rammed his car into a police checkpoint in a Paris suburb, injuring two officers. The 29-year-old suspect, identified as Youssef T., was not on France's list of people suspected of radicalisation or being security threats. But investigators found a knife and a letter swearing allegiance to IS jihadists in the black BMW he used to plough into police cars and motorcycles as officers carried out traffic stops on Monday evening. The man wrote that he wanted to "throw his body and soul into the battle to impose Shariah law across the Earth," prosecutors said. He was taken into custody for questioning, and a psychiatric evaluation did not reveal any mental troubles. "Given the circumstances, the national anti-terror prosecutor's office has decided to open an investigation on charges of attempted murder of persons holding public authority as part of a terrorist operation," the office said. France's DGSI domestic security agency is also assisting the inquiry, it said. The two motorcycle police suffered leg fractures and remain hospitalised. France has been on high alert over a wave of jihadist attacks on its soil since January 2015, when gunmen stormed the Charlie Hebdo satirical newspaper in an attack that killed 12 people, including police officers. Since then over 250 people have been killed by people often claiming allegiance to the Islamic State militants. bl/js/pvh