Police confirmed that 30 people died in the Grenfell Tower fire in West London on Wednesday and warn the death toll is expected to rise further.

Firefighters at the Grenfell Tower block which was destroyed in a disastrous fire, in north Kensington, West London, Britain June 16, 2017.  [Photo/Agencies]

The news comes amid fierce criticism of Prime Minister Theresa May's handling of the tragedy, as well as fresh allegations that a recent renovation of the building used materials banned in the United States.

The BBC reported on Friday that as many as 76 people are missing following the blaze that engulfed the 24-storey building, owned and built by the local council. It housed mainly low-income families, many of them immigrants.

Prime Minister May said there will be a public enquiry into the cause of the fire. May visited officials and firefighters at the site on Thursday, though her failure to meet with survivors brought heavy criticism from the public and political opposition.

Defence Minister Tobias Ellwood said May did not meet residents due to security concerns. On Friday, the Queen and Prince William both met volunteers, local resident and community representatives at a temporary relief shelter in Westway Sports Centre near the tower. Labour Party leader Jeremy Corbyn and London Mayor Sadiq Khan both met those affected by the fire on Thursday.

Conservative Party politician and Leader of the House of Commons Andrea Leadsom visited Grenfell Tower on Friday where she was confronted by residents angered by May's actions. It is now understood that the Prime Minister will visit victims of the fire in hospital on Friday.

As investigations continue into how the fire started and how it was able to get out of control so quickly, The Times reported on Friday that the type of cladding that allegedly encased the building is banned in the United States.

According to the report, a type of aluminum paneling called Reynobond was fitted to the exterior of the building in a renovation completed last summer. There are three types of Reynobond paneling - two have fire-resistant cores while one has a flammable plastic core. It is believed the subcontractor that fitted the panels used the latter type which is marginally cheaper.

Reynobond with a plastic core is banned for use in the US in buildings taller than 12.2 meters, and is used primarily for small commercial buildings. Grenfell Tower rises above 67 meters.

The Metropolitan Police has launched a criminal investigation into the tragedy, and the London Fire Brigade said the search of the structure will be a "slow and painstaking process."

So far six of the dead have been provisionally identified. The first of the victims named was Mohammed Alhajali, a 23-year-old Syrian refugee who arrived in the UK in 2014.

Metropolitan Police Commander Stuart Cundy said there was a risk that "sadly we may not be able to identify" all of the victims due to the intensity of the blaze.