DENMARK midfielder Christian Eriksen received CPR on the pitch after collapsing during his country's Euro 2020 game against Finland in Copenhagen.
Inter Milan player Eriksen dropped to the ground at the Parken Stadium shortly before half-time, leaving players from both teams in clear distress.
English referee Anthony Taylor called medics on to the pitch and Eriksen underwent prolonged treatment.
Team-mates formed a shield around the former Tottenham man, while fans inside the stadium were clearly stunned by the incident, with some pictured in tears.
A tweet from UEFA said the match had been suspended due to a medical emergency.
Fabrice Muamba, the former Bolton midfielder who collapsed after suffering a cardiac arrest during a televised FA Cup game in 2012, has responded to the news of Eriksen's collapse.
"Please God," tweeted Muamba.
Christian Eriksen's former club, Tottenham, tweeted: "All of our thoughts are with Christian Eriksen and his family."
Eriksen left Tottenham for Inter Milan in 2020 after seven years with the club.
Dozens of current and former players have posted messages of support for Eriksen, including his Inter Milan team-mate Achraf Hakimi.
"Eriksen Please," tweeted the Moroccan international.
Others posting similar tweets for the Denmark midfielder include former Liverpool defender Jamie Carragher and Manchester United's former right-back Gary Neville as well as current England and Aston Villa forward Jack Grealish.
UEFA later said Eriksen had been transferred to hospital and stabilised.
The governing body said further information on the situation would be communicated at 18.45 UK time.
"Following the medical emergency involving Denmark's player Christian Eriksen, a crisis meeting has taken place with both teams and match officials and further information will be communicated at 19:45 CET," read the UEFA tweet.
"The player has been transferred to the hospital and has been stabilised."
The Football Association released a statement, which read: "Our thoughts this evening are with Christian Eriksen and his family, and all connected with the Danish Football Union."
Denmark tweeted an update which read: "Christian Eriksen is awake and is (set) for further examinations at Rigshospitalet (hospital)."