An altercation between Richard Petty Motorport's Marcos Ambrose and Germain Racing's Casey Mears has resulted in both men being handed fines and probationary periods by the sanctioning body.

Tempers flared on pit road after Saturday night's Toyota Owners 400 Sprint Cup Series race at Richmond International Raceway when an argument between Marcos Ambrose and Casey Mears turned physical. TV cameras caught Mears shoving Ambrose away and the Australian responding by landing a punch on the side of Mears' head before the two were separated by members of their pit crews.

The exact cause of the fight remained unclear. "It was a few things on the track," Mears told Fox Sports 1 on Monday. "At the end of the day, none of that should ever happen, but in the heat of the moment when you get out of your race car and it just happened to you some stuff that you didn't like, we started going at each other.

"Before we knew it, it escalated really quickly," he continued. "For a moment there, I kind of wanted to hit him, but I thought I can't do that. So I grabbed him." Asked if things had subsequently been resolved with Ambrose, Mears replied: "I think so, for the most part, [but] you never forget getting hit."

"I was actually heading over to have a chat with David Gilliland," recalled Ambrose. "I was confused about why Casey was so annoyed at me ... He was mad at the race and he was mad at himself and we were around each other at the end of the race. It's a full contact sport out there. I'm charged up. I'm full of adrenaline too.

"That passion kind of got out of hand and got out of control pretty quick," Ambrose continued. "To be honest with you, once he put his hand on me and started pushing me around I was just trying to stand up for myself and my country and my family and my reputation and I threw a punch down on him to get him out of the way and let him know that I didn't respect him not giving me my private space."

After reviewing the tapes of the incident, both drivers were deemed to have violated Sections 12-1 (actions detrimental to stock car racing), and 12-4.9 (Behavioral Penalty; involved in an altercation in the garage area after the race) as outlined in the 2014 NASCAR rule book.

As a result, Ambrose has been fined $25,000 and placed on NASCAR probation until May 28, while Mears has been fined $15,000 and also placed on probation until the end of May.

Speaking before the announcement, Mears had indicated that he was unsure whether he or Ambrose would be penalised and was actually hoping that NASCAR's response over the incident would provide some guidance. "I don't know how to distinguish what I'm able to do next time," said Mears. "Professionally, I want to know where that line is."

The video tapes of the clash had also appeared to show a third unidentified (and unpenalised) party 'sucker punch' Ambrose in retaliation after the two drivers were pulled apart, but Ambrose himself explained the the latter punch did not in fact find its target.

"I did not get punched, I was able to duck and weave and get out of trouble," he said. "The person in question, I haven't seen the footage, so I don't know if there was a swing thrown, but there certainly was aggression at the end. I've had a phone call from somebody to apologise for his actions and that's it for me. I've got no beef with him, either.

Ambrose has confirmed that he will accept the penalty from NASCAR and a statement from Richard Petty Motorsport said that he would not be exercising his right of appeal.

"I'm happy to move on and put the week behind us. It's certainly not a proud moment of mine, but I certainly don't take anything back that I did," he said. "I was just standing up for myself and standing up for my family and you get to a point where you've got to defend yourself and that's exactly what I did."

And Ambrose was sure that there would not be a lasting feud between himself and Mears over the incident.

"Casey and I spoke about it and he said, if the shoe was on the other foot he probably would have done the same thing," he said. "I think we have a mutual respect for each other, I like Casey a lot ... I'm not carrying anything forward. He has to decide what he wants to do moving forward, but if we get ourselves in a pub somewhere I'd buy him a beer no problem."