LONDON – London Mayor Boris Johnson says Britain's counter-terrorism forces are monitoring "thousands" of potential extremists in the metropolitan area.
The Daily Telegraph newspaper on Saturday quoted Johnson as saying the security forces in the London area are involved in "thousands of operations" every day. He said the number of people being watched is in the low thousands.
Five young men arrested earlier this week for questioning about a possible terrorist plot are still being held and a number of residences have been searched.
Government sources, speaking on condition of anonymity, have said the men arrested this week include one who recently returned from Syria and police are probing possible ties to the Islamic State group operating there.