The British government is monitoring thousands of terror suspects in London, Mayor Boris Johnson told the Telegraph newspaper on Friday night, as the official terror threat in the UK remained at “severe” level.
“In London we’re very, very vigilant and very, very concerned,” Johnson said. “Every day — as you saw recently, we had to raise the threat level — every day the security services are involved in thousands of operations…there are probably in the low thousands of people that we are monitoring in London.”
In late August the UK’s terror threat risk level was raised to “severe,” meaning an attack was “highly likely”. It was the second highest level out of five possible categories and the highest since July 2011.
The increase has been tied to developments in Syria and Iraq, and Britain’s involvement in the fight against the Islamic State group there, which could encourage retaliatory attacks by British extremists.
It has been estimated that approximately 500 UK nationals have traveled to fight in the region, with the Telegraph reporting that about half have returned home for various reasons.
“London has a particular concern,” Johnson said, “because probably of the five or six hundred that are out there, we think a third, maybe more — maybe half — come from the London area. If and when they come back, we have a real job to deal with them.”
On Wednesday London police questioned four terrorism suspects believed to have been plotting an attack inside Britain and were checking a possible link to the Islamic State group.
Officials said that a medical student was among the group of four suspects, which includes one man who had traveled to Syria. The men, aged 20 and 21, were arrested Tuesday morning in London.
British media identified the medical student as Tarike Hassan, known as “the surgeon” among his friends. Reports also indicate he is the same suspect who traveled to Syria and is suspected of meeting with militants there.
The Times of London reported that he had landed back in the UK 48 hours before he was arrested in a raid on Tuesday in which he was tasered. He had allegedly traveled from Sudan where he was studying.
Brit Tarik Hassane sent tweet laughing at beheaded Kurdish woman soldier http://t.co/I9FpDpOyf9
— News This Second (@NewsThisSecond) October 9, 2014
On the day he was arrested, Hassan reportedly tweeted “I smell war.” His friends told the Times the tweet referred to a dispute with a group of girls and was not an indication of a plot to attack the UK.
Neighbors described a young man who grew increasingly devout over the past few months. While in Sudan, Hassan “was known to associate with some Salafist or fundamentalist students,” The Telegraph reported.
According to the Daily Mail, Hassan also used social media to call on followers to pray for jihadi fighters in Syria and to allegedly ridicule a female Kurdish fighter beheaded by an Islamic State jihadist.
AFP and AP contributed to this report.