Paris: French President Francois Hollande on Friday paid tribute to the police couple killed at their home by an Islamic State fighter and warned that the war against terrorism will be long. Hollande's remarks came in a speech honouring Jean-Baptiste Salvaing and Jessica Schneider, killed at their home in Magnanville on the outskirts of Paris, in an attack claimed by Islamic State, Efe news reported. He stressed before hundreds of police officers that the two were killed because they were police officers and they embodied the republic. Hollande said that in recent months security forces had foiled many attempted attacks. He said French justice will act with severity against these attacks, adding officers may keep their weapons when they were off duty, even when the state of emergency, currently in force in France, finally ends.