NEW : London media reports name Nine of those arrested as radical cleric Metropolitan Police . The men , aged from Friday , were all detained in UK , police say . UK authorities estimate that 500 Britons have gone to Syria and Iraq to fight with Islamist groups . The men arrested are suspected of belonging to and supporting a banned organization . The arrests `` are not in response to any immediate public safety risk , '' police say .
NEW : London media reports name Nine of those arrested as radical cleric Metropolitan Police . The men , aged from Friday , were all detained in UK , police say . The men arrested are suspected of belonging to and supporting a banned organization . The arrests `` are not in response to any immediate public safety risk , '' police say .