Three men arrested in England in connection with the Manchester terror attack have been released without charge.
Greater Manchester Police said two men, aged 20 and 24, from the Fallowfield area, and a 37-year-old man from the Blackley area have been released.
Detective Chief Superintendent Russ Jackson, head of the North West counter terrorism unit, said: "The release of some people can be expected in investigations of this nature as we corroborate accounts that have been provided."
Eleven people are still in custody after being arrested following a number of raids across the country in the wake of the suicide bombing.
Mr Jackson said more than 1,000 officers had been working on the investigation to piece together what happened and whether others had worked with 22-year-old bomber Salman Abedi.
He added: "Much of the investigation has been painstakingly working through Salman Abedi's last movements. We have done this by examining his movements on CCTV and other interactions he has had whether it be with people or the phone calls he has made.
"With specialist support we have also have a good understanding of the likely component parts of the bomb and where these came from.
"Our inquiries show Abedi himself made most of the purchases of the core components and what is becoming apparent is that many of his movements and actions have been carried out alone during the four days from him landing in the country and committing this awful attack."
Mr Jackson said it was "vital" to ensure that Abedi had not been part of a "wider network" and that this could not yet be ruled out.
"There remain a number of things that concern us about his behaviour prior to the attack and those of his associates which we need to get to the bottom of.
"We are especially keen to find out why he kept going back to the Wilmslow Road area and we need to find the blue suitcase which he used during these trips," he said.