A woman arrested by counter-terrorism police investigating the London and Glasgow bomb plots has been released without charge, a Scotland Yard spokesman said.
Marwa Asha, 27, was arrested with her husband, Dr Mohammed Asha, 26, of Newcastle-under-Lyme, Staffordshire, on the M6 motorway in Cheshire on June 30.
Police are continuing to question four men, who are all being held at London's high security Paddington Green police station.
Two are trainee doctors, aged 25 and 28, who were arrested at the Royal Alexandra Hospital, Paisley.
A 26-year-old doctor from Bangalore, India, who worked at Halton Hospital in Runcorn, Cheshire, was arrested in the Lime Street area of Liverpool on June 30.
Also under police guard is a man arrested after a flaming Jeep was driven at Glasgow Airport. He is being treated for burns and is in a critical condition in hospital.
Dr Asha and the 26-year-old doctor from Bangalore can be questioned until Saturday.
The two trainee doctors arrested at the Royal Alexandra Hospital can be held for a further day, until July 15.
On Saturday, an Iraqi doctor became the first person to appear in court charged in connection with the suspected car bomb plots in London and Glasgow.
Bilal Abdullah was remanded in custody when he appeared at City of Westminster Magistrates' Court in London. The 27-year-old, who was arrested after the Glasgow Airport incident, is accused of conspiring to cause explosions.
