Cameroon midfielder Marc-Vivien Foe died on Thursday after collapsing during his country's Confederations Cup semi-final against Colombia.
Foe, who spent last season on loan at English premier league Manchester City from French club Olympique Lyon, was carried off on a stretcher after collapsing towards the end of the match, won 1-0 by Cameroon.
Alfred Mueller, FIFA's Swiss medical officer for Lyon, told a news conference: "I have to give you very sad information. The player Marc-Vivien Foe has died.
"This is a very sad day for football, for FIFA and for the player's family. This is all we can say at the moment."
FIFA, who said there would be an autopsy to determine the circumstances of the death, later issued a statement saying Foe had "collapsed to the ground in the second half, around the 72nd minute, for no apparent reason.
"The player was still alive when he was taken to the medical centre in Gerland Stadium in Lyon, where he died. Doctors performed cardiac resuscitation for 45 minutes without success."
It quoted Mueller as saying: "It is too early to determine the exact causes of his death."
FIFA president Sepp Blatter expressed his shock and sadness at Foe's death, but said the tournament ought to continue and that Cameroon should go ahead with their final against France on Sunday at the Stade de France.
Blatter learned the news, along with the crowd and the teams, at the same Paris venue before the second semi-final between France and Turkey, which the hosts won 3-2.
"FIFA and the whole family of football are shattered by this unbelievable tragedy," he said in a statement.
"On their behalf, I wish to convey our sincerest condolences to his family and loved ones, to Cameroon football and his club, and express all our support at this painful time. Football has lost a remarkable player and a remarkable man."
In an interview with French television at halftime in Paris, Blatter said: "As for the rest of the competition, we'll have to think about what to do.
"My opinion is that, in a competition like the Confederations Cup, the football should continue. We are sad, but the game continues.
"It's not the show, but the football that must go on."
In Lyon, FIFA press chief Hedi Hamel said players of both teams were in a state of shock and, forgoing their showers and still wearing their match kit, joined each other in prayers.
"They were stunned and it was a moment of great emotion for the Colombian players who were also in a state of shock.
"There is great solidarity among them and an extraordinary chain of friendship has been formed.
"A lot of Colombian players prayed immediately after (news of Foe's death) and were joined (in prayer) by the Cameroon players," he said.
"It was a terrible scene."
Hamel also said: "Marc-Vivien Foe was with us yesterday and the day before, he seemed happy and enjoying life. His one love was to play football and he really wanted to play this match."
Foe, 28, played 65 games for Cameroon and formerly played for West Ham United and RC Lens.
The powerful midfielder missed the 1998 World Cup through injury, but played in all three of Cameroon's games in last year's tournament, having done the same in 1994.
He produced impressive form for Manchester City in the season just finished, but the club decided against paying Lyon seven million pounds ($11.65 million) to take him to England on a permanent basis.
A minute's silence was observed before the other semi-final in Paris.
France's goalkeeper Gregory Coupet, a Lyon team mate of Foe, appeared distraught, while Thierry Henry, who opened the scoring for the hosts shrugged off his team mates' congratulations and pointed to the sky.
"The first goal was for him," he said afterwards.
Henry's gesture brought tears to the eyes of France manager Jacques Santini, the former coach of Foe's Lyon, who were French champions in 2002.
"There is nothing to say," Santini said. "It's really hard for those who knew him.
"We are going to miss him."
