At a press conference on Saturday, Belotti said Friday morning's blaze could have been caused by power surges resulting from wild storms that hit Rio de Janeiro a day earlier, reports Xinhua news agency.
"The assumption now is that these energy spikes affected the regular operation of the air conditioning and caused the fire to start," Belotti said. "It was a succession of events after a catastrophic day for Rio that led to this even greater catastrophe," he added.
All 10 of the deceased were aged between 14 and 16 and were either already contracted with the club or undergoing trials.
Rio's city government said after the incident that it had asked Flamengo "nearly 30 times" to close the facility because it did not have the appropriate permits. The city said the dormitory was built in an area that was only licensed for use as a parking lot.
"That (the absence of permits) doesn't have anything to do with what occurred," Belotti said. "We've been asked to show nine certificates and we have eight. We are working on it with the fire department.
"This area was well known to everyone. It was comfortable and adequate. We were proud of it. The truth is that it was a tragic accident. It was not because of a lack of investment or care by Flamengo."
The three injured survivors remained in hospital on Saturday, one in a serious condition, according to a Rio health department spokesman.
Ten other teenagers who were sleeping in the dormitory when the fire broke out escaped unharmed.
Rio mayor Marcelo Crivella declared three days of official mourning as a mark of respect to the victims. Flamengo's Guanabara Cup semi-final against Fluminense was shifted from Saturday to next Thursday.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)