Searches of the park are expected to take up to three days
Counter-terrorism officers are searching a public park in north Manchester, police have confirmed.
Officers are using metal detectors and dogs to scour part of Heaton Park, four miles north of the city centre.
Police say the searches - part of an ongoing operation following raids in north-west England on 8 April - could last three days.
Twelve men arrested in Manchester, Liverpool and Clitheroe, Lancashire, were later released without charge.
A spokeswoman for Greater Manchester Police, said: "Officers from the North West Counter Terrorism Unit are currently searching an area of Heaton Park in north Manchester.
"This is part of the ongoing counter-terrorism operation."
The searches began at 0830 BST on Thursday at the park, which is about two miles from Cheetham Hill where several addresses were raided in the operation.
Police appeared to be concentrating on an area around 200 yards inside the boundary, between a boating lake and a pitch-and-putt course.
Officers in black boiler suits used spades and sticks to clear undergrowth at a heavily wooded area alongside a brook.
Police have not indicated what they are trying to find.