Two people arrested in connection with the bombing on a London Underground train last week have been released without charges, the Scotland Yard announced Thursday.
A 21-year-old man arrested in Hounslow, west London, on Saturday and a 48-year-old man arrested in Newport, south Wales, on Wednesday were both released. Four other men, aged 17 to 30, remain in police custody.
None of the suspects has been charged, and their names haven't been released.
Thirty people were injured when a homemade bomb, placed inside a bucket wrapped in a shopping bag, partly detonated on a train stopped at London's Parsons Green station during rush hour September 15.
The attack sparked a manhunt for the perpetrators and prompted officials to briefly raise the national terrorism threat to the highest level.
Police said they are continuing their investigations and are searching several properties across the country.