Real Madrid teenager Vinicius Junior joined Brazil legends Zico and Pele in an outpouring of sorrow after a fire at the training center of Brazilian club Flamengo claimed 10 lives on Friday.
The early morning blaze, which also left at least three people injured, occurred while youth team players and staff slept at a dormitory inside the Ninho do Urubu complex in Rio de Janeiro's western neighborhood of Vargem Grande.
"What sad news! Praying for everyone! Strength, strength, strength," Vinicius, who began his career at Flamengo before his July 2018 move to the Bernabeu, said in a Twitter post.
"Just remembering the nights and days that I spent there [at Ninho do Urubu] makes me shiver. I still don't believe it. My prayers for all."
Former Flamengo and Brazil great Zico posted a heartfelt video on Instagram from Japan, where he is currently the technical director of Kashima Antlers.
"May the red and-black army have the strength and faith to get through this moment," the 65-year-old said. "I ask God to comfort the families of these boys who had dreams. It needs to be investigated because lives are gone and there is no turning back."
Three-time World Cup winner Pele said: "My day began with the news about the fire at Flamengo's training center - a place where youngsters pursue their dreams. Its a very sad day for Brazilian football."
Brazilian President Jair Bolsonaro, who is recovering in hospital after an operation to remove a colostomy bag fitted last September, was not immediately available for comment. However the government's press secretary released a statement lamenting the loss of lives.
"Dismayed, the president ... expresses his solidarity with family members during this time of mourning," it read.
Former Arsenal midfielder and 2002 Brazil World Cup winner Gilberto Silva also posted condolences on social media, as did a number of high-profile clubs, including Atletico Madrid and AC Milan.
Six of the deceased were youth players, all of whom had their identity confirmed on Friday afternoon, according to the Globo newspaper. Authorities said the names of the victims would not be released publicly until all family members were informed.
Survivors taken to hospital were Jonathan Cruz Ventura, 15, Emanuel Gomes Nunes, 14, and Francisco Diogo Bento Alves, 15, according to Rio's municipal health department. The most serious injuries were suffered by Ventura, who had burns to around 40% of his body, a health official said.
Fire department spokesperson Douglas Henaut said the cause of the fire, which was restricted to the complex's dormitory area, was still unknown. According to a Flamengo youth team player around 30 people were sleeping at the facility when the blaze began.
In a statement, Flamengo said the club would "not spare any effort to probe the cause and minimize the suffering of the families of the victims."
The tragedy followed days of torrential rain and gale force winds that killed at least six people in the city. Vargem Grande and its surrounding neighborhoods were among the areas hardest hit by the storms, which caused severe flooding and landslides.