Seven of the 11 people arrested in connection with the Westminster terror attack have been released, Metropolitan Police said on Friday.

Two men – a 58-year-old man and a 27-year-old man, both from Birmingham – still remain in police custody.

Police raided addresses across the country earlier this week – including in London, Manchester and Birmingham – as they looked to establish whether Westminster attacker Khalid Masood acted alone or with accomplices who directly encouraged, supported, or directed him.

The attack on Wednesday killed four people and injured 50 as Masood drove a car into pedestrians on Westminster Bridge, before stabbing a police officer – PC Keith Palmer – who died from his injuries. Two people are currently in a critical condition – one with life-threatening injuries – in hospital.

Masood was shot dead by police on the scene on Wednesday.

Of those arrested:

    A 39-year-old woman arrested at an address in east London on suspicion of preparation of terrorist acts has been released on bail until a date in late March A 32-year-old woman arrested in Manchester was bailed pending further enquiries until a date in late March. A 35-year old man arrested in Manchester was released with no further police action. A 21-year-old woman arrested at an address in Birmingham was released with no further action. A 23-year-old man arrested in Birmingham at the same address was released with no further action. A 26-year-old woman and three men aged 28, 27, and 26-years-old who were arrested at separate addresses in Birmingham were also all released with no further action.