Testing of explosives found at London high-rise scene were combustible

LONDON -- British Prime Minister Theresa May's office says combustible cladding has so far been found on seven high-rise blocks in England after tests ordered by the government.

The British leader said earlier Thursday that tests were being carried out on cladding on apartment blocks across the country because of concerns that the building material helped spread the fire that engulfed Grenfell Tower in West London in the early hours of June 14. At least 79 people died in the blaze.

May had earlier told lawmakers that three samples had tested as being combustible.

May's office says that around 600 buildings in England have cladding similar to the type blamed for the quick spread of flames in the London high-rise disaster.

Councils in England made the estimate as authorities desperately try to get a grip on the scale of the issue facing local authorities following the blaze at Grenfell Tower that killed at least 79 people on June 14.

The cladding on the building has been singled out for scrutiny because the blaze engulfed the building in less than an hour. That has surprised fire officials, who have wondered aloud how a 24-story building could become an inferno so quickly.

May has also announced that the investigation into whether the tower met fire safety regulations will be published in the next 48 hours.