Story highlights
- Authorities searching a number of addresses around southern England
- Four men are arrested on suspicion of terrorism offenses, the Metropolitan Police says
- They are being held in London police stations while officers search homes and vehicles
- Police: Arrests "are part of an ongoing investigation into Islamist related terrorism"
British authorities overnight arrested four men for suspected terrorism, police said on Friday, adding to the scores that have been rounded up in recent months as part of efforts to prevent homegrown attacks.
The men, ages 19 to 27, were rounded in four different southern England locales between 8:31 p.m. (3:31 p.m. ET) Thursday and 2:55 a.m. Friday, according to London's Metropolitan Police.
Armed police -- who are rarely deployed in the United Kingdom -- took part in three of the arrests, though no shots were fired, the Metropolitan Police said.
The force's Terrorism Command, working with the regional South East Counter Terrorism Unit and Britain's intelligence agency MI5, made the arrests as "part of an ongoing investigation into Islamist-related terrorism."
The four are hardly the first to be taken into custody for suspicions tied to Britain's Terrorism Act 2000.
Assistant Commissioner Mark Rowley said last month that counter-terrorism officers were "running exceptionally high numbers of counter-terrorism investigations, the likes of which we have not seen for several years."
In the year up to October 17, there had been 218 terror-related arrests, he said, adding that officers are disrupting "several attack plots a year."
UK authorities searching addresses
The UK government raised its terror threat level from "substantial" to "severe" -- the fourth-highest of five levels -- in late August in response to ISIS militants' surge in Iraq and Syria and their threats against the West. At the time, Home Secretary Theresa May said "that means that a terrorist attack is highly likely, but there is no intelligence to suggest that an attack is imminent."
Many of the most recent terrorism-related arrests have been in London, the nation's capital and site of deadly coordinated 2005 suicide attacks, as well as the 2013 slaying of British soldier Lee Rigby.
Three of the latest arrests occurred at addresses in west London and the Thames Valley area, to the west of the capital.
The fourth man was in a car in the Southall district of west London when he was taken into custody, according to police.
Even after those arrests, authorities weren't done.
They searched at least six different addresses in the region, from west London as far west as High Wycombe.
As of late Friday afternoon, the Metropolitan Police said, "The searches are ongoing, enquiries continue."
