Detectives investigating the disappearance of midwife Samantha Eastwood are carrying out searches in a rural area of Stoke-on-Trent.
Specialist search teams are looking at an area of Caverswall as part of their search for the 28-year-old, Staffordshire Police said.
Officers have cordoned off a section of land and are carrying out painstaking searches in their effort to look for clues, the force added.
Eastwood was last seen in her uniform leaving work at Royal Stoke Hospital at 7.45am on Friday July 27.
Her colleagues raised concerns at 7.20pm on the same day after she failed to show up for her next shift.
Dozens of specialist officers and police dogs have been combing an area of fields next to a country lane.
The search, in close proximity to Tickhill Lane, began just after 9am on Saturday following a police briefing at Cheadle Police Station.
Uniformed officers could be seen looking into bushes using large sticks as they scoured the vast rural area.
A police spokesman said Staffordshire Police are the only force currently involved in the searches.
An occupant of a neighbouring farm to where police are searching said officers had asked to view footage from his CCTV camera of the night Samantha Eastwood disappeared, but the camera didn’t have enough memory to go back that far.
Nigel Potts, 53, who owns Newhill Farm, said he had seen more police activity down by a nearby disused quarry.
After he had passed the quarry on Saturday morning, Mr Potts said: “There was a minibus, a van and half a dozen cars I’d say.
“It seems that that’s where the main focus of the search is. They’ve been down here for three days.”
A 32-year-old Stoke-on-Trent man was arrested earlier in the week but has since been released under investigation, Staffordshire Police said.
The force said neighbours reported hearing a scream in the vicinity of the midwife’s house at about 2pm on the day she went missing.
Detective Superintendent Simon Duffy from the force’s major and organised crime department said: “Today’s extensive searches are part of the ongoing investigation, which has officers and staff working round the clock in an effort to find anything which brings us closer to finding Samantha.
“I am calling on any member of the public with any information, however small and insignificant it may seem.
“Have you seen any unusual or suspicious activity, including parked vehicles in laybys in rural locations around the Stoke-on-Trent/North Staffordshire area?”
Eastwood’s sister, Gemma Eastwood, made a tearful appeal for help in tracing her on Friday, saying: “We miss you very much, we need you home where you belong.
“If she’s out there, or anyone knows where she is, please get in touch.
“Get her home.”