Round-the-clock work is continuing to fix a damaged dam at risk of bursting and flooding a Derbyshire town.
Teams are pumping water from Toddbrook Reservoir near Whaley Bridge, after part of a dam ruptured.
More than 1,000 homes have been evacuated since the breach on Thursday and there is concern nearby Marple, Stockport, is also at risk of flooding.
Police warned Whaley Bridge residents officers would stop allowing them back to their homes because of the risk.
A meeting for residents will be held later to explain the current situation with the operation.
A "handful" of people who have refused to leave their homes have been advised "personally and in no uncertain terms" of the risks they are taking, a Derbyshire Police spokesman said.
He emphasised the exclusion area was being treated like the cordon at a crime scene and anyone putting themselves in danger would be "dealt with accordingly".
URGENT UPDATE: WHALEY BRIDGE— Derbyshire Police (@DerbysPolice) August 4, 2019
The decision has today, Sunday 4 August, been taken to stop allowing evacuated residents back to their homes in Whaley Bridge. This is effective immediately.
On Saturday, people were allowed briefly into their homes to collect pets and essentials, but were warned they would be doing so at their own risk.
One resident per household was escorted by police back into their homes for 15 minutes.
Deputy Chief Constable Rachel Swann said the risk during those trips "was extraordinarily high" and they had caused problems.
"The vast majority of those who have been allowed back in to Whaley Bridge have been fantastic," she said.
"However, there have been a very small minority of people who have returned to their homes and have not presented back at the road block at which they entered.
"These people are putting the lives of officers at risk as further checks have to now be completed to ensure those residents are out of the area safely."
Some 1,500 people in Whaley Bridge had sought shelter elsewhere after part of the reservoir's spillway broke away on Thursday.
Father Jamie Mcleod, who lives in the town, said he had hardly slept for three days, taking supplies to the emergency workers.
'Started to crack'
He was here at the start of the crisis when he went to check the dam after days of heavy rain.
"When I was over there it started to crack," he said. "When it got worse I went over to the council and raised the alarm and said, 'We have to evacuate the village'.
"We then went back to the reservoir and, of course, the police then came and procedures were put in place.
"At the time I really thought the village was going to go.
"Then it really struck me there is a school at the bottom of the dam and last week that playground was full."
After a long night pumping water at #WhaleyBridge we needed to relocate our High Volume Pump. Physical work at 04:30 but the beautiful setting and sunrise took away the pain. Great work #Rugeley crew. pic.twitter.com/BrHnPRhHJl— Staffordshire Fire & Rescue Service (@StaffsFire) August 4, 2019
Twenty-four pumps are working and more than a third of the reservoir's water had been removed since Thursday, lowering the level by three metres (9ft) officials said.
But forecasters say 30-40mm (1.2-1.6in) of rain may fall in two hours, later on Sunday.
Police said the "risk of adverse weather" was to blame for the most recent evacuations.
Nine-year-old Caitlin decided however, the main concern was her grandfather's chickens
When your school holiday plans are disrupted by a "dam flood"! Please save the chickens Grandad (and the trampoline). Love from C xxx #whaleybridgedam #whaleybridge #SummerHolidays pic.twitter.com/jUwGSzo7TG— Jo Jo Amour (@littlejo2010) August 4, 2019
The army and police officers have also visited residents in Marple, issuing flooding advice.
Emergency responders are planning and preparing for a "potential incident" but were not yet evacuating that area.
Earlier on Sunday, Derbyshire Deputy Chief Fire Officer Gavin Tomlinson said teams at Whaley Bridge had made good progress.
"We now know we have taken around 35% of the contents of reservoir out now and we are aiming to get it down about 25% where we think it is at a safe level," he said.
The reservoir has sloping sides and as the water level drops the pumps have to be moved closer to the water's edge, he said.
'Not out of the woods'
An RAF Chinook helicopter has placed 525 one-tonne bags to strengthen the dam wall and regulate water flow.
Daniel Greenhalgh, from the Canal and River Trust, which owns the reservoir and dam, warned: "We are not out of the woods yet.
"The last estimate was that residents could be out of their homes for seven days yet."
Police, the Environment Agency, and the Canal and River Trust have all said there is a "real risk" the 188-year-old dam could collapse and flood the town.
The trust has defended the maintenance and safety of the structure, which was built in 1831.
Our officers are out with colleagues from @BritishArmy @manchesterfire delivering important flood safety messages alongside @StockportMBC to residents in #Marple #Stockport. We continue to liaise with @DerbysPolice as they monitor the situation in #WhaleyBridge pic.twitter.com/iHNrEdcwt0— Greater Manchester Police (@gmpolice) August 3, 2019
Mr Greenhalgh said: "This dam is inspected regularly, by us and an independent engineer.
"It needs to be remembered there was a huge amount of rain in a short time and this flooded the area."
The Met Office has issued a yellow weather warning for much of northern England and the Midlands, including the area around the reservoir, until 00:00.
BBC Local Radio news special on the emergency in Whaley Bridge and surrounding areas near the River Goyt on BBC Radio Manchester, Sheffield and Derby from 18:00 through the night. Reporters in key areas and regular updates from emergency services.