She went on to call the claim "pure speculation", and said the information is not a leak from Britain.
"The joint terrorist analysis centre, which reviews the threat level that the United Kingdom is under, has made a decision to lower that level from critical to severe".
Ms Rudd's announcement comes just hours after police arrested a second man in connection with the bombing.
ANTI-terror cops have swooped on a home directly opposite Heathrow Airport after a second man was arrested in the hunt for the Parsons Green bomber.
Police are continuing to search a house in Sunbury-on-Thames in Surrey.
Gov't forces rescue abducted priest, professor from Marawi City
The rubble-strewn streets of Marawi were practically empty except for scores of heavily armed soldiers securing the area. In a statement, Armed Forces of the Philippines-Public Affairs Office (AFP-PAO) chief Marine Col.
Of the 30 people injured in the bombing, all but one have been discharged from hospital.
The health service said Sunday that one person is still being treated at Chelsea and Westminster Hospital, which has a special unit for treating burns.
He reportedly "froze" as he was surrounded by cops at 7.50am yesterday after being tracked by facial recognition technology following the London Tube attack that injured 30.
The property being searched by counter-terrorism police investigating the London subway bombing belongs to an elderly couple who have for years taken in foster children.
The whole road remains cordoned off and police have erected a large grey fence around the front of the Jones's home.
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The koala was dubbed Kelli, the name of one of the firefighters who came to her rescue. Its should have been very hot in there, "Jane Brister said at Reuters".
Friend Alison Griffiths said the couple had an 18-year-old and a 22-year-old staying with them recently.
Police arrested an 18-year-old man earlier on Saturday following the attack in west London.
"Good progress" with the ongoing operation had led the Joint Terrorist Analysis centre to lower the threat level, said home secretary Amber Rudd.
London police say a second man has been arrested in connection with the London subway attack.
On Sunday, Scotland Yard said that a 21-year-old man had been arrested in Hounslow, south-west London, shortly before midnight.
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She stated, "I believe we offered sufficient evidence that proved beyond a reasonable doubt that Jason Stockley meant to kill Mr. The mayor did not appear to be in, and some 200 police in full riot gear used tear gas to disperse the crowd.