Assistant referee Constantine Hatzidakis will not be involved in any matches while the Football Association investigate whether he elbowed Liverpool's Andrew Robertson.

The extraordinary incident occurred just after the half-time whistle had been blown during Liverpool's explosive 2-2 draw against Premier League leaders Arsenal at Anfield on Sunday.

Robertson appeared to confront Hatzidakis on the pitch, reaching to grab the arm of the official, who reacted by jabbing his elbow towards the Liverpool left-back.

Robertson gesticulated that he had been hit by Hatzidakis while the irate Scotland captain was led away by team-mates, only to receive a yellow card in the aftermath of the bizarre incident.

Hatzidakis is under FA scrutiny for his role in the row and will be sidelined until the governing body's probe is complete.

A statement from Premier League referees' body the PGMOL read: "PGMOL will not be appointing Constantine Hatzidakis to fixtures in any of the competitions it serves whilst the FA (Football Association) investigates the incident involving the assistant referee and Liverpool defender Andrew Robertson at Anfield."

Keith Hackett, formerly head of the PGMOL, told BBC Radio Five Live: "Ultimately, if he is found guilty of this, his career is in jeopardy.

"I was trying to find an excuse as to why he did it and I came up with was he in fear? He shouldn't be, because he's in a protected environment with plenty of security.

"But he reacted in a way that he shouldn't have reacted at the end of the day and here we are talking about a match official and not a decision, but an action by a match official -- and he's clearly lost his composure."

Big baby

Another former top-flight referee, Mark Halsey, put the spotlight on Robertson's behaviour but admitted a ban is the most likely punishment for Hatzidakis if he is proven to have committed an offence.

Writing in The Sun, Halsey drew a parallel with Fulham striker Aleksandar Mitrovic, who was recently banned for eight matches for pushing referee Chris Kavanagh.

"To me, it looks like Robertson goes to grab Hatzidakis, who brushes him off with his arm and catches him accidentally," Halsey said.

"I cannot think why an assistant would throw his arms into a player's face. Sure, from one camera angle it does not look good. But you have to ask why has Robertson gone to approach the assistant referee?

"I have heard people say this is the end of the linesman's career but, just like Aleksandar Mitrovic, it is his full-time job. However, if he is proven guilty and did intentionally use his elbow then he will face the same consequences as the Fulham frontman."

Liverpool boss Jurgen Klopp said he did not see what had happened, but Sky Sports pundits working on the game reacted with incredulity.

Gary Neville, the former Manchester and England defender, said: "I've never seen an official raise an elbow to a player. I think he'll be in a lot of trouble after this game ends."

Former Manchester United captain Roy Keane focused on Robertson's role in the incident.

"He should be more worried about his defending," said Keane. "Do you know what he is, that Robertson? I've watched him a number of times, he is a big baby, that's what that guy is."