Before the match, a picture was cut in from the VAR room where the referee, Australian Shaun Evans, held his hand down along his leg, with his thumb and index finger forming a ring and his fingers pointing downwards.
The Fare network, which works with the International Football Federation (FIFA) to identify discriminatory chants, flags and symbols at matches, described the sign as "neo-Nazi", according to the AP.
"It is clear that this referee should have no further role to play in this World Cup," the network wrote in a statement.
The gesture can also be interpreted as the "OK" sign, according to the AP.
FIFA said it was aware of the incident but did not want to comment further, The Athletic reports.
