Liverpool players accused linesman Constantine Hatzidakis of elbowing Andrew Robertson at half-time during today's draw against Arsenal.
Robertson approached Hatzidakis, who then appeared to raise his arm towards the defender.
Liverpool players surrounded referee Paul Tierney following the incident, with Robertson receiving a yellow card.
"I think the linesman throws an elbow," said Jamie Carragher on Sky Sports.
Touchline reporter Geoff Shreeves then reported: "'Andy Robertson was absolutely apoplectic, Stunned even.
"He said: 'He's just elbowed me in the throat. The linesman has elbowed me in the throat'.
"Jordan Henderson led the remonstrations with referee Paul Tierney, then they got taken away. Extraordinary scenes."