More government support is needed to help tackle a wildfire on the Lancashire moors, Greater Manchester Mayor Andy Burnham has said.
While visiting the scene at Winter Hill near Bolton, Mr Burnham said the "brilliant" firefighters needed "air support" to deal with the blaze.
He added that he wanted to ensure "all necessary resources are available".
Full firefighting operations resumed at first light on Monday, Lancashire Fire and Rescue Service (LFRS) said.
The fire has been raging for five days.
Mr Burnham said he would be seeking to speak with Home Secretary Sajid Javid "to relay what I've seen and ask the government to take a closer interest in what is happening here".
"The firefighters have been doing a magnificent job... but what I take away from being here is that they need more support, possibly air support," he added.
"This remains a challenging situation and we need to ensure that all necessary resources are made available."
There are 17 fire engines currently at the Winter Hill wildfire until full firefighting operations resume at first light pic.twitter.com/hCr7xrntJR— Lancashire Fire (@LancashireFRS) July 1, 2018
Up to 100 firefighters from across England are tackling the blaze on Winter Hill, which started on Thursday, in "testing conditions".
A major incident was declared when winds caused two fires to merge near communication masts on Saturday.
The flames have spread close to Grade II-listed Rivington Terraced Gardens, which received £3.4m of lottery funding two years ago for improvements.
LFRS said people were spotted lighting fires nearby by a helicopter.
Two engines were sent to a wooded area at Healey Nab at 13:30 BST on Sunday, and the fire was contained within about two hours.
Alan Wright from the Wildlife Trust for Lancashire, Manchester and North Merseyside has been surveying the damage.
He said he saw a butterfly searching for food in a "poignant" moment demonstrating what is missing for wildlife, the food sources and nesting areas.
He said the wildlife "will come back but it will take a while… it'll take a few years to be anywhere near where it was beforehand".
We continue to support the operation led by @LancashireFRS on Winter Hill this weekend. Primarily we are there to provide moorland safety cover for personnel involved in the firefighting operation; we're also conveying food & water onto the hill to keep crews replenished. 1/2 pic.twitter.com/UirvHeghOC— Bolton MRT (@BoltonMRT) July 1, 2018
2/2 With so many organisations involved its impossible to name them all, fire crews inclu Warwickshire, Humberside, Northumberland & South Wales. Also Coastguard, United Utilities, specialist aircraft, police, ambulance, councils etc 1 huge team & we're proud to be a part of it. pic.twitter.com/1N63rIJhbG— Bolton MRT (@BoltonMRT) July 1, 2018
The Winter Hill blaze, near a major TV transmitter, is smouldering in pockets and it is feared the moorland blaze may burn for another week.
Mark Scott, assistant team leader at Bolton Mountain Rescue Team, said six sq miles (16 sq km) of the moors had been burnt.
He said: "We have dealt with a number of moorland fires over the years but nothing on the scale of this. This dwarfs anything we have seen before by a huge measure."
A 22-year-old man, from Bolton, arrested on suspicion of arson with intent to endanger life has been released under investigation.
Lancashire Police said it was continuing to investigate the cause of the fire.
The fire comes as crews from across the country, along with the Army, combat a blaze 30 miles away at Saddleworth Moor in Greater Manchester, which started a week ago.
Along with the Winter Hill fire, it has covered the region in smoke and ash.
Speaking in the Commons about the fire at Saddleworth Moor Stalybridge MP Jonathan Reynolds said he was "surprised" no meeting of the government's emergency committee Cobra was held in the wake of the moorland fires.
But Minister of State for Policing and the Fire Service, Nick Hurd, told MPs the moorland fires near Saddleworth Moor in Greater Manchester and across the border in Lancashire at Winter Hill, near Bolton, "remain major incidents" and the government was "fully engaged".
Lancashire Wildlife Trust said a separate "devastating" fire on Saturday destroyed a large part of a nature reserve in St Anne's, Lancashire.
More devastating news. On Saturday a fire on our Local Nature Reserve in St Anne's destroyed approx 20% of the reserve's habitat. The cause is unknown. Please don't light bbqs on dry grassland, and dispose of all litter, particularly glass bottles & cigarette butts. pic.twitter.com/34MRCkfQR2— Lancs Wildlife Trust (@Lancswildlife) July 2, 2018
There is also a large grassfire burning in the Staffordshire Moorlands.
Gary Keary, chairman of the Fire Brigades Union in the North West, said crews were being pushed "to their limits" and claimed fire services were having to rely on donations for basic supplies such as sun cream and water.
He said: "Our firefighters have been working in difficult conditions to keep the fire from spreading and have done an amazing job," but added "it is deeply saddening that we have had to reach for the begging bowl".
At the scene: Paul Keaveny, BBC News Online
After a couple of minutes at the top of Winter Hill, my eyes were streaming and I was covered with ash.
The charred ground was giving off heat and dense clouds of smoke as the wind swirled and changed direction, conditions which crew manager Stu Hall, of Tyne and Wear Fire and Rescue, said were a particular challenge.
"I think we are making an impact but it keeps breaking out in different places," he said.
Looking out across the blackened moorland, the scale of the fire hits you - the helicopter dropping water appears tiny in this huge landscape.
Back down the hill in nearby Horwich, you could be forgiven for thinking the fire had gone out, as the smoke dissipated into the hot clear sky - but the smell of smoke on my shirt and my stinging eyes tell a different story.
People in nearby areas have been asked to keep doors and windows closed.
Police have also repeated their advice for people to stay away after a man collapsed from smoke inhalation when he ignored police cordon tape.
They have also warned people against trying to fly drones over moorland in efforts to record footage.
Paul Etches, head of prevention at Greater Manchester Fire and Rescue Service (GMFRS), warned the moorland fires were "not going away" and it would take "many more days of intense sweat and effort" to extinguish them.
"Our firefighters are tired but optimistic that we continue to make good progress," he said.
Dave Keelan, assistant chief fire officer with GMFRS, said the service had the challenge of two major incidents as firefighters are still dealing with moorland fires in Tameside.
"I cannot praise my firefighters enough, they have done a fantastic job," he said.
Mr Keelan also thanked the firefighters from other parts of England and Wales who have been on duty.
"We have been very, very fortunate. Without the support of other fire services it would not have been business as usual."