"The police are investigating this man, his associates, where he came from, checking urgently whether other people are involved in this… The working assumption is that this is related to Islamic terrorism in some form," Fallon told the BBC broadcaster.
The defense secretary stressed that the investigation was still ongoing and the police did not have the full understanding of what motivated the attacker, his background and potential associates.
The latest police reports indicate that seven arrests had been made in connection with the Wednesday attack that led to the deaths of two members of public and one police worker, with 29 people being treated in hospital. The man drove his car into pedestrians on Westminster Bridge and then attempted to enter the building of the parliament, armed with a knife, before being shot.
