Hearts on Sunday revealed they had launched an investigation into reports of abuse targeted at Rangers striker Alfredo Morelos, while Bristol City said they were looking into allegations racist language was used in the away end during Saturday’s Championship match at Luton.

Roma issued an apology on Sunday evening for racist chanting towards Sampdoria’s Ronaldo Vieira and said they would punish those responsible, while on Monday Serbia were ordered to play next month’s Euro 2020 qualifier against Luxembourg behind closed doors because of racist behaviour by supporters.

A United spokesperson said the club were aware of an incident at the Liverpool match “where an individual in the home section has allegedly engaged in racial abuse”.

The spokesperson added: “The individual was identified and ejected from the stadium. We are currently investigating the matter as a priority.

“Racism and all forms of discrimination are completely unacceptable and do not reflect the values of our club.”

It is understood the situation could lead to an indefinite ban.

A Liverpool spokesperson said the club took “all allegations of this manner extremely seriously” and would “support the strongest possible action being taken against anyone found to be responsible”.

The spokesperson praised “the swiftness with which Manchester United have launched an investigation”.

Saturday’s FA Cup fourth qualifying-round match at Haringey’s Coles Park ground saw the players walk off in the 64th minute, shortly after Yeovil had gone 1-0 up via a penalty.

Haringey said on Twitter that the game had been abandoned following racist abuse and their defender Coby Rowe wrote on his account that he had been a victim.

As well as Rowe receiving racist abuse from the crowd, Haringey goalkeeper Douglas Pajetat was spat on and had a bottle thrown at him, Borough chairman Aki Achillea has said.

The FA said that the match would be replayed on October 29 at Haringey, with November 5 the potential replay date in the event of a draw. Yeovil said the game would kick off at 7.45pm.

Earlier on Monday two men were arrested in connection with the abuse during the first game. The Metropolitan Police said the men – aged 23 and 26 – had been arrested in Chard and Yeovil on suspicion of racially aggravated common assault.

The pair have been held in custody at a Somerset police station. Metropolitan Police officers are leading the investigation with the help of Avon and Somerset Police.

The FA said its investigation into the incident was ongoing.

Northampton said the allegations from Saturday’s game with Salford at Sixfields concerned “the chanting of words that are offensive and discriminatory towards the traveller community”.

Hearts vowed to ban any fan found guilty of racism from their Tynecastle ground indefinitely following reports Morelos was the target for abuse after scoring during Sunday’s match.

Police Scotland said they are aware of the allegations and are “liaising” with both clubs.

Elsewhere, the Football Association of Serbia was charged with a series of offences surrounding September’s 4-2 defeat by Portugal in Belgrade, and now UEFA’s control, ethics and disciplinary body has handed down a two-match ban on spectators, the second of which is suspended for a 12-month probationary period, “for the racist behaviour of its supporters”.

“The Serbian FA is ordered to display a banner with the wording ‘#EqualGame’, with the UEFA logo on it, in the next UEFA competition match which the association will play as the host,” the governing body said.

The Serbian FA has also been fined a total of 33,250 euros – around £28,540 – for the other charges, which included pitch invasions by spectators, the use of fireworks, “illicit chants” and a late kick-off.