Leicester City fans laid flowers on the club's pitch, as they waited for official news on the fate of owner Vichai Srivaddhanaprabha, whose helicopter crashed outside the ground.
The occupants of Srivaddhanaprabha's helicopter have not been officially confirmed, but a source close to the family told the BBC that the 61-year-old was on the chopper that crashed shortly after take-off from the stadium on Sunday (NZ time).
Tributes flooded in for the owner, who took over in 2010 and helped Leicester claim their unlikely Premier League triumph in 2016.
"I know the whole Srivaddhanaprabha family and the father, and what he has done for Leicester is incredible," former Leicester and England manager Sven Goran Eriksson told BBC Radio 5 Live.
"He took the club from second division up to the first division, winning it and made them a big Premier League club.
"When you know him as I do - and, of course, the whole team and all the staff - you know that he is a very, very generous man."
Other Premier League clubs offered their support and thoughts via social media, as well as former players, including Gary Lineker and Peter Shilton.
"Thoughts are with everyone at Leicester City," Lineker tweeted. "A terrible tragedy. Heartbreaking."
So far, the rescuers have not given details of the number of victims, but the occupants of the helicopter are unlikely to have survived. Reports suggest one of Srivaddhanaprabha's two daughters, two pilots and one other person were in the aircraft.
Sky News reported that Srivaddhanaprabha had been at the match and that the helicopter had taken off from the pitch soon after.