Fernando Varela scored with a header in the 90th minute, putting the home team, Paok, ahead 1-0 and on course to close the gap between themselves in third spot and leaders AEK.
The referee signalled a goal but then seemed to disallow it for offside.
Paok’s owner, the businessman Ivan Savvidis, came on the field twice and was accompanied by bodyguards. On the second occasion, without the overcoat he was wearing before, Savvidis appeared to be carrying a pistol which was in its holder.
AEK officials claimed Savvidis threatened the referee during his first foray onto the pitch, before being pulled away.
The game was suspended and the crowd was told to disperse. Adding to the widespread confusion, there were claims that the referee, Giorgos Kominis, had allowed the goal.
The Superleague’s website recorded the match as a 0-0 draw and showed AEK still leading the table on 55 points, with Olympiacos in second on 53 points and Paok still in third on 50.
An official statement was expected from the league.
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