Police are evacuating an area of Moss Side in Manchester as fresh arrests and raids are carried out linked to Monday's suicide bombing.
A property was being searched as Greater Manchester Police attempt to close the net on the suspected terror network behind attacker Salman Abedi.
Officers were said to have been taking precautionary measures to ensure public safety.
Two men aged 20 and 22 have been held on suspicion of terror offences after officers used an explosive device to gain entry to a property in the Cheetham Hill area of the city.
The operation in the early hours of Saturday morning brings the number of suspects being held in custody to 11.
The development came as a vast security operation gets under way to protect hundreds of spring bank holiday events across Britain this weekend.
It followed searches at a separate property in Cheetham Hill and an address in the Longsight area in south Manchester.
Residents described hearing a "loud bang" as the latest raid and a controlled explosion took place in Brideoak Street in Cheetham Hill..
Shakufta Bi, who lives across the road, said the noise woke her in the early hours and she saw the street full of police cars and vans along with men in green military uniforms.
Mrs Bi said a Libyan family live at the address - a mother, three sons in their late teens or early 20s and a daughter. The father, an engineer, lives in Dubai and visits occasionally.
All the sons pray at a mosque 200 yards away, known locally as the "Libyan" mosque.
Some neighbours report seeing the sons wearing both "western" dress and traditional Islamic robes.
Another neighbour, Val Jones, said: "I heard a loud bang, it sounded like a door getting kicked in. Then I looked out the window. I seen a lot of police going to the bottom end then I seen a convoy of cars, just normal, private, unmarked cars from the bottom of the street to maybe where that taxi is.