Second suspect held after London train attack

UK police said Sunday morning that they had detained a second suspect, a 21-year-old man, late Saturday in Hounslow on the western rim of London. He was detained under Britain's Terrorism Act, following the Friday bomb attack on an underground train in London which injured over 20 people.

On Sunday, the British government lowered the country's official terror threat level from the highest, designated as "critical," to the second-highest, or "severe."

"Severe still means that an attack is highly likely so I would urge everybody to continue to be vigilant but not alarmed," Home Secretary Amber Rudd said in a televised statement.

The terror militia "Islamic State" claimed responsability for the attack, but Rudd told the BBC there was no evidence to confirm the group's involvement.

Investigators work 'at great pace'

Police said that were receiving numerous calls from the public through the special anti-terrorist hotline.

"We have identified 121 witnesses so far, and we have spoken to 100 of them already. Officers continue to trawl through many hours of closed circuit television footage and more than 180 videos and pictures that have been sent to them by the public," Senior National Coordinator for Counter Terrorism Policing Neil Basu said in a statement on Saturday.

"We are still pursuing numerous lines of enquiry, and at great pace," Basu told reporters.

Prime Minister Theresa May put Britain on"critical" late on Friday, with soldiers and armed police deploying to guard strategic locations such as nuclear power plants. The last time Britain was put on "critical" alert was after a suicide bomber killed 22 people at the Ariana Grande concert in the northern city of Manchester in May. Prior to that it had not been triggered since 2007.

Sunbury raid

Police in forensic suits were seen on Saturday afternoon entering a house in Sunbury, 11 miles (18 kilometers) from Parsons Green where the explosive device was set off on Friday morning. Thirty people have received treatment at hospital for injuries sustained on the train.

The house in Sunbury reportedly belongs to Ron and Penny Jones, who were honored by Queen Elizabeth in 2008 for their fostering of children, who have included refugees and asylum seekers in recent years, according to press reports.

Teenager questioned in London

On Saturday, an 18-year-old was detained in the departure lounge of the cross-Channel ferry port of Dover, on the south east coast. He was transferred to London where he has been questioned by police.

"This is a very significant arrest," said interior minister Amber Rudd.

"The police have made very good progress but the operation is ongoing," she said, following a meeting of the government's emergency Cobra committee. The Cabinet Office Briefing Rooms, often referred to as Cobra, are the locations for meetings of a crisis response committee to co-ordinate the actions of government and security agencies.

"Communities across the UK will continue to see more officers, both armed and unarmed, on patrol by foot and in vehicles over the remainder of the weekend. In particular, they will be patrolling at crowded places, iconic sites, transport hubs and ports" Basu said in his statement on the ongoing investigation.

jbh, se/jm (Reuters, AFP)