Alwaght- British police have detained a second man has been arrested over connections with Friday’s explosion on a London underground train that injured 30 people.
The 21-year-old man was arrested in the west London suburb of Hounslow just before midnight on Saturday, the Metropolitan Police force said in a statement.
He was taken to a south London police station and remains in custody.
Earlier on Saturday, British police arrested an 18-year-old man in the port of Dover and raided a property in Sunbury, a small town outside London, as they hunted for whoever planted the device.
A search was also carried out at a house in Sunbury-on-Thames, Surrey, at the home of foster care couple Penelope and Ronald Jones, who previously received MBEs for services to children and families.
The couple are said to be staying with friends for at least the next five days following the police raids, during which surrounding houses were evacuated by counter-terror officers, with residents told they had "one minute" to flee their homes.
Friends said the couple - foster parents for almost 40 years who had taken in up to 300 children, including eight refugees - had an 18-year-old and a 22-year-old staying with them recently.
British Prime Minister Theresa May raised the terror threat level to critical in the wake of the bomb, meaning another attack is imminent.
The home-made bomb, which apparently failed to detonate properly, was the fifth major terror attack in Britain this year and was claimed by the ISIS Takfiri terrorist group.
The Takfiris have claimed other attacks in the UK this year, including two in London and one at a pop concert in Manchester.
May said military personnel would take over guard duty at certain “protected sites,” freeing up police to be deployed on the transportation network and on streets across the country.
“For this period, military personnel will replace police officers on guard duties at certain protected sites,” May said in a televised statement.
“The public will see more armed police on the transport network and on our streets providing extra protection. This is a proportionate and sensible step which will provide extra reassurance and protection while the investigation progresses,” she added.
The use of military personnel to assist police is part of Operation Temperer, a British government measure designed to deploy troops at important security points to help police following terrorist attacks.