Cairo (CNN) -- At least 73 people were killed when riots broke out after a soccer game in Egypt Wednesday, a spokesman for Egypt's health ministry said.
At least 180 others were injured in the rioting, spokesman Dr. Hisham Shiha said. Most of them had concussions and deep cuts, he said.
The fighting occurred in a stadium in the northeastern city of Port Said after Al-Ahly team beat Port Said's Al-Masry team 3-1.
Fans from both sides bashed each other with rocks and chairs, said Mohamed Sultan, head of the ambulance association in Port Said.
Rescuers treated 60 people on the ground, he said, and dozens of ambulances were at the stadium.
Authorities are investigating what caused the clashes, said Adel Saeed, a spokesman for Egypt's general prosecutor.
While authorities were responding to the fighting in Port Said, a fire broke out in Cairo stadium. It was not immediately clear if the incidents were related.
Soccer riot death toll climbs in Egypt
"It's kind of a security vacuum in the football stadium. ... It's not unheard of to have organized violence between football clubs, but something on this scale has never been seen before," said James Montague, a CNN contributor who researched soccer in the Middle East for his book "When Friday Comes: Football in the War Zone."