State broadcaster NRK reported on its website that the 27-year-old Torp collapsed in the closing minutes of Brann's Norwegian championship match at Sogndal. He had come on as a substitute in the 79th minute.
"He has suffered a cardiac arrest," Brann team doctor Asla Kjeldsen was quoted as saying.
"We can not say anything yet, other than that right now he is stable and it's going well.
"We used a defibrillator and CPR on the way off the pitch," said Kjeldesen, adding that Torp was "stable and conscious" as he was loaded onto the air ambulance which had landed in the middle of the pitch.
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