Police are investigating an incident between Cardiff defender Krystian Bielik and home supporters during Portsmouth’s 2-0 Championship win on Saturday.

Bielik was involved in a physical altercation with a fan as he went to retrieve a ball from the crowd late in the second half.

Cardiff head coach Brian Barry-Murphy claimed afterwards that Bielik “got slapped in the face”, while clips circulating on social media appeared to show the Poland international grabbing a young fan around his upper body.

Hampshire Police says an investigation into an alleged assault is under way.

“We can confirm that we are investigating an incident in which a teenage boy was reportedly the victim of a common assault during the football match at Fratton Park. Our enquiries are ongoing,” the police said.

Several Portsmouth supporters made gestures that indicated they believed the fan had been grabbed by the throat.

In the aftermath, another fan threw a ball at the head of Cardiff defender Perry Ng, while both supporters were ejected from the stadium.

After the game Portsmouth head coach John Mousinho apologised to Cardiff City’s players.

Pompey added in a statement: “Portsmouth Football Club are aware of supporter concerns regarding the incident involving a young fan and an opposition player at yesterday’s match at Fratton Park.

“As this remains a safeguarding matter and is currently under investigation by both the club and the police, it would be inappropriate for us to comment further on the circumstances at this time.

“However, we are aware that a number of claims and assertions are circulating on social media. We would urge caution against speculation while enquiries are ongoing.

“The welfare and safeguarding of young people are of paramount importance to Portsmouth Football Club. We will continue to liaise with the relevant parties as enquiries progress.

“No further comment will be made at this stage while investigations remain ongoing.”

The Football Association is aware of the matter and will review the details in the referee’s match report before deciding whether any action should be taken.

Cardiff City said: “We are satisfied with the way that match officials dealt with the situation during the game, having been in full view of it. Player protection will always be of paramount importance to us.”