Professional Footballers' Association chief executive Gordon Taylor has called for urgent action to stop football fans invading pitches to confront players before a 'tragedy' occurs.
Two supporters were arrested for separate pitch invasions on Sunday with Aston Villa player Jack Grealish punched during their derby match with Birmingham City.
And Manchester United defender Chris Smalling was shoved by a pitch invader during their defeat to Arsenal later in the day.
The incidents came after Rangers player James Tavernier was confronted by a spectator during their match at Hibernian on Friday night.
And PFA Chief Taylor is concerned these incidents are part of a worrying trend of anti-social behaviour at football grounds in Britain this season.
He told Sky Sports: 'It was disgraceful, cowardly and criminal but we have seen an increase in such behaviour at clubs this season.
'There has been racist abuse, there has been anti-Semitism and now there is real fear for the safety of players.
'From that point of view, we had a meeting just the other week with the Minister for Sport, Mims Davies, about engaging on this issue between the police and the stewards, which is crucial, and the responsibility of clubs.
'We need to find the right balance between educating supporters who are there, and also having sanctions.
'We have to make sure we put a lid on it. We have been down this road before and we do not want to go there again and see the game threatened.'
Taylor called for discussions between the government, police authorities, football clubs and stewards to curb the rise of such behaviour before a player is seriously harmed.
'These are criminal acts,' Taylor said. 'If it happened on the high street there would be severe action taken. There is no reason why that should not be done just because it is a football ground.
'There is a combination of sanctions [for clubs] with fines, ground closures, games behind closed doors and points deductions. Every case will be looked at on its merits.
'It has almost been a copycat of what has been happening. We have had three incidents this weekend. We have had other incidents this season.
'It seems to be a time when these things are coming back. We need to improve the atmosphere.
'You can have commitment and enjoyment and it is great entertainment but when it bubbles over to this it is no longer what we want it to be. It is about setting an example.
'We have been warned now on too many occasions. This has got to be dealt with by the football bodies, the police, the stewards and the clubs. There is a total responsibility.
'We have got to address it now. If not, it is going to be too late and there is going to be a tragedy.'
Birmingham City fan Paul Mitchell, 27, will appear in court on Monday over the incident at St Andrew's Stadium in which he attacked Grealish, 23, with a punch from behind after running onto the pitch.
The married father-of-one, of Rubery, near Birmingham, has been banned from the club for life.
Mitchell saluted fellow Birmingham fans, some of whom applauded his actions, as he was removed from the pitch by stewards.
The incident occurred in the ninth minute of the game when flat-cap wearing Mitchell ran onto the field from the Tilton End and appeared to punch Grealish in the head from behind.
The 23-year-old fell to the floor but was not badly hurt. A steward, helped by both sets of players, then restrained Mitchell.
Shortly after the incident Grealish scored what would end up being the match-winning goal and jumped over the hoardings to celebrate.
A steward restraining him appeared to kick the Aston Villa captain and was later led away by police.
Later in the afternoon at the Emirates Stadium, a spectator ran onto the pitch and pushed United and England defender Smalling shortly after Arsenal had scored their second goal.
Smalling was unhurt and the fan was taken off the pitch and arrested after running over to celebrating Arsenal players.
An Arsenal spokesperson said: 'We utterly condemn the behaviour of the individual who ran on to the pitch and approached Chris Smalling during today's match.
'We would like to apologise to Chris and Manchester United, and are pleased that [the spectator] was apprehended and arrested. We will be working closely with the Metropolitan Police in their investigation.
'The individual will also be banned from Arsenal matches home and away. Our matchday staff receive ongoing training on managing incidents such as this.'
Shortly after the match, a statement from the Metropolitan Police said: 'A man has been arrested on suspicion of common assault and pitch invasion following an incident during the Arsenal v Man Utd game at the Emirates Stadium today.
'He is currently in custody at a north London police station.'
A 21-year-old was arrested after he ran onto the pitch to confront Rangers captain Tavernier during their match at Hibernian's Easter Road stadium on Friday night.
The man attemped to kick the ball away from Tavernier as he moved to pick it up to take a throw in. The two then laid hands on each other before the fan was led away by police.