The list of high-rise apartment towers in Britain that have failed fire safety tests grew to 60, officials said Sunday, revealing the mounting challenge the government faces in the aftermath of London's Grenfell Tower fire tragedy.

All of the buildings for which external cladding samples were so far submitted failed combustibility tests, Communities Secretary Sajid Javid said. As of late Sunday, that includes 60 towers from 25 different areas of the country- double the figure given a day earlier.

The number of buildings at risk is likely to grow as owners and local officials provide more samples for safety tests.

The national testing was ordered after an inferno engulfed Grenfell Tower in west London on June 14. The tower's cladding - panels widely used to insulate buildings and improve their appearance - was believed to have rapidly spread that blaze, which killed at least 79 people.

In north London, officials trying to avoid another fire disaster sought to complete the evacuation of hundreds of apartments in four towers deemed unsafe. 

They faced resistance as some 200 residents refused to budge.

Camden Council ordered residents from some 600 apartments at Chalcots Estate to evacuate late Friday as a precaution after fire inspectors found problems with the blocks' fire doors and gas pipes.

The council said residents must leave immediately because of those issues and because the towers were encased in similar cladding to the material used at Grenfell Tower.

Hundreds were put up in hotels and other temporary accommodation. The evacuees now face up to four weeks in limbo as workers try to upgrade the buildings' fire safety features. Council leader Georgia Gould said those still staying in their homes must leave for the renovations to begin.

Sayed Meah, 34, who lives with his mother and wife, said he would not move until the company that helps care for his mother agrees to provide service at a new location.

He said he and other residents are determined to remain in their apartments until a legal notice is obtained or they are "dragged out by their fingernails."

Refurbishment of the Chalcots towers was overseen by Rydon, the same company involved in the recent renovation of the now-devastated Grenfell Tower.

A public inquiry is due to determine how the unsafe cladding was allowed to be fitted onto Grenfell and other buildings in the first place.

London Mayor Sadiq Khan backed the Camden Council's decision to evacuate the apartment blocks.

"I think they've done the right thing. Look, you've got to err on the side of caution. You can't play Russian roulette with people's safety," Khan told Sky News.

AP