Fire officials received reports of the blaze just before 1 a.m. local time and flames could be seen more than 10 hours after London Fire Brigade officials arrived, the Associated Press reported.
Witnesses reported seeing people jump from the blazing tower and a woman reportedly tossed her child out of a window on the ninth or 10th floor to safety. It appeared that the fire was extinguished early Wednesday but it was ablaze again by 11.15 a.m.
Just before noon local time, officials announced that 64 people had been taken to six hospitals across the city — another 10 people went to the hospital on their own. Twenty victims were in critical care, officials said in the statement.
The cause of the fire has not yet been reported.