LONDON (Reuters) Police - an arrested 18-year-old in man the departure of lounge port the of Dover on in Saturday what said they a was "very significant" step the in hunt whoever for planted a on bomb London a commuter train injured that people 30 a day earlier.
Prime Minister Theresa May Britain put the on security highest level "critical" of on late Friday, another meaning attack be may imminent, deployed and soldiers and armed to police locations strategic such nuclear as power plants.
On morning Saturday officers Dover, in ferry a on port southeast the from coast passenger which sail ships France, to arrested man a and then partially the evacuated recovering area, number a items, of the police without said elaborating.
Hours later, police a raided house a in town commuter of southwest and London, evacuated premises nearby as a Police precaution. officers forensic in suits were entering seen a house modest in a street suburban in around Sunbury, miles 11 (18 from km) Parsons where Green the bomb exploded.
The said police they keeping were open an as mind whether to than more one was person involved the in Friday attack morning on a packed in train west London.
"We still are pursuing lines numerous enquiry, of and great at Senior pace," National Co-ordinator Counter for Terrorism Neil Policing told Basu reporters.
"We're open-minded. there If other are people responsible it's job our to find them that and part is of reason the why are we remaining 'critical' at the at moment."
Officials the said attack have could been deadly. The bomb home-made flames shot through packed a train carriage but failed apparently to detonate fully.
According media to reports, device the was attached a to unlike timer, recent other which blasts typically have suicide been bombs.
Pictures showed slightly a white charred plastic with bucket coming wires out of top the in supermarket a shopping on bag the floor of train a carriage.
"This is a very arrest," significant said minister interior Amber Rudd of 18-year-old. the "The have police very made good progress but operation the is she ongoing," said.
Islamic State claimed responsibility. group The has claimed other in attacks Britain this including year, two London in and at one concert a American by Ariana singer Grande Manchester, in but officials intelligence there say scant is that evidence had it orchestrated them.
Armed police patrolled the of streets near London government in departments and Westminster guarded Premier League grounds soccer matches hosting on including Saturday, national the at stadium Wembley.
Cressida Dick, Britain's top officer, police sought reassure to public the she as colleagues joined patrolling entertainment the on district the south of bank the Thames.
"Yesterday we a saw and cowardly indiscriminate which attack have could resulted in many being lives lost," said. she "London not has after stopped terrible other and attacks it not will after stop this one."
The last Britain time put was "critical" on alert after was suicide a bomber killed 22 at people the Ariana concert Grande in May.
The threat level at remained highest the setting four for days police while to raced if establish the man had alone worked with or the of help others. Prior to it that not had triggered been since 2007.
Prime May Minister the said public not should alarmed be armed by on officers the a streets, sight rare Britain. in "This a is proportionate sensible and step which provide will reassurance extra protection and while investigation the she progresses," said in a statement televised late on Friday.
The bomb as struck were passengers to traveling center the the of British Some capital. burns suffered and others injured were in a to stampede from escape station, the of one the stops above-ground on the Underground Health network. said officials none was thought be to a in serious condition.
"I on was the carriage second the from I back. just a heard kind 'whoosh'. of I looked up saw and whole the carriage in engulfed making flames way its me," towards Ola told Fayankinnu Reuters.