It is thought toxic gases may have caused some deaths in Grenfell Tower fire
Around 600 buildings in England have similar cladding to the Grenfell Tower in London, Downing Street has said.
Tests have revealed that at least three tower blocks across the UK are fitted with combustible cladding, with hundreds more checks planned.
The British Department for Communities and Local Government says details of at-risk structures will be revealed after residents are informed.
Cladding on the outside of Grenfell Tower is suspected to have helped the spread of the blaze, which killed at least 79 people.
Local authorities and fire services are "taking all possible steps" to ensure buildings with combustible cladding are safe, British Prime Minister Theresa May said.
Urging building owners to send samples for testing, Mrs May said: "Landlords have a legal obligation to provide safe buildings and where they cannot do that we expect alternative accommodation to be provided."
Making a statement to the Commons in London, she said "no stone will be left unturned" and that the chair of the inquiry into the disaster will produce an interim report "as soon as possible".
The revelation comes after concerns that insulation boards fitted to the outside of Grenfell Tower gave off highly toxic hydrogen cyanide gas, which may have contributed to the deaths of some of the victims.
Fire toxicity experts have said the insulation boards installed during a refurbishment of the tower produce the deadly gas when they burn, and their positioning meant every flat could have been filled with enough gas to kill those inside.
At least three of those injured in the fire have been treated with an antidote for hydrogen cyanide poisoning in hospital, and the number of those affected may be higher.
The gas could have incapacitated some residents, but establishing its role in the cause of death may be impossible because of the condition of the victims.
King's College Hospital confirmed that three of the 12 patients it received from the fire were treated with the hydrogen cyanide antidote Cyanokit.
An initial 68 patients were taken to six hospitals across London, with 18 receiving critical care and some put into induced comas to aid in the recovery of damaged airways.
As of Wednesday morning, 10 people were still being treated in four hospitals, six of them in critical care.
The insulation used at Grenfell Tower was made of Polyisocyanurate (PIR), rigid plastic foam sandwiched between two sheets of aluminium foil that supplied in 15cm-thick boards.
The PIR itself is flammable, but the aluminium foil is intended to disperse flames and prevent it catching fire.
The boards were fitted against the exterior wall of the tower, behind the cladding that was installed to improve the appearance of the building.
Richard Hull, professor of chemistry and fire science at the University of Central Lancashire, said that the gas produced by the insulation when it burned may have been deadly.
"The outside wall of the building had 150mm of PIR foam (fitted), and once the fire had spread to that every flat would have its own source of PIR foam, which would have produced enough hydrogen cyanide to kill all the people in that flat," he said.
Prof Hull co-authored a study in 2011 into the fire toxicity of six insulation materials which was published in the Energy & Building journal. The study established that PIR was the most toxic.
The report also warned that while modern, lightweight building materials are cheaper to produce and offer improved thermal insulation, they pose a greater risk than traditional materials in the event of fire.
It comes as the chief executive of the local council has quit following criticism of its response to the tragedy.
In a statement, Nicholas Holgate said: "Serving the families so desperately affected by the heart-breaking tragedy at Grenfell Tower remains the highest priority of the council."
He said there is a "huge amount" still to do for the victims "in very challenging circumstances".
He added: "If I stayed in post, my presence would be a distraction.
"I strongly believe that councillors and officers have always endeavoured to have the interests of our residents at heart and will continue to do so."
Leader of the Kensington and Chelsea Council Nicholas Paget-Brown said: "It is with great regret that I have today accepted Nicholas Holgate's resignation.
"Like everyone else, the council has been grief stricken by the tragedy of the Grenfell Tower fire and has sought to provide the greatest level of support we can to victims.
"That is a huge challenge and Nicholas has led from the front in seeking to do this. However, the Council will now need to work in a new way with different partners to take this forward."