London: Two of the six men arrested in connection with last week's bombing in the London subway have been released without charge, the Scotland Yard has said.
One of those released is a 21-year-old, who was arrested on Saturday from Hounslow in West London. The second man, 45 years of age, was held from Newport in south Wales on Wednesday.
Four other men, arrested in connection of the bombing, remain to be in the police custody.
"We anticipate that the searches will take some days to complete and may cause further disruption. However, it is important that we continue with these searches and I'd like to thank all those affected for their support, patience and cooperation," Dean Haydon, head of the Metropolitan Police's counter-terrorism command said.
He also appealed to the public to remain vigilant and report anything suspicious to the police.
Thirty people were injured last Friday when a bomb partially exploded on a rush-hour tube train in south west London.
The 21-year-old man who was released has not been officially named but is believed to be Yahyah Farroukh, a Syrian refugee.
Besides questioning those in custody, the police are searching properties in Newport in Wales, Thornton Heath in south London, and Surrey areas.
Westminster Magistrates' Court has granted the permission to police to continue questioning the remaining men until next week.
A home-made bomb went off on Sept. 15 during the morning rush hour on a packed underground Tube train at Parsons Green station, sending flames through the carriage, although it appeared that the device did not fully explode.
It was the fifth major militant incident in Britain this year.
The Islamic State militant group, which had said it was behind several attacks on Western cities in recent years, including two attacks in London and one in Manchester this year, claimed responsibility for the latest attack.