Ashley Williams understands Robin van Persie anger

Swansea City defender Ashley Williams has admitted that he understands Robin van Persie's frustration after he kicked the ball at the striker's head during Sunday's draw with Manchester United.

United boss Sir Alex Ferguson claimed that the striker could have been killed following the incident in the 1-1 draw at the Liberty Stadium.

Referee Michael Oliver had already blown his whistle before Van Persie was struck - which led to a scuffle between both sets of players.

"Everyone's going to have their own opinion but from my point of view I tried to apologise on the pitch but it all flared up," Williams told Sky Sports News.

"I just kicked the ball in frustration and obviously not trying to hit him square on the head.

"I understand exactly why he's angry. I'd be the same if the ball hit me on the head at that pace."

Ferguson has since urged the Football Association to ban Williams for the "disgraceful act".