Lee Trundle holds a flag on which a message is daubed

The insult was daubed on a Welsh flag held aloft by Swansea players celebrating their 2-1 win over Carlisle at the Millennium Stadium.

South Wales Police said they were also investigating the incident.

Swansea player Lee Trundle was also pictured wearing a T-shirt bearing an insulting cartoon.

The neighbouring clubs have a history of rivalry.

FAW secretary general David Collins said he was at the match but did not see the incident.

He told BBC Wales: ''I shall complete the investigation and then decide what action, if any, should be taken.''

Mr Collins said he hoped to finish his inquiry on Tuesday.

Lee Trundle put the cartoon T-shirt on top of his football jersey

Meanwhile, the Football League said it "deplored" the actions of the Swansea players.

"One would hope that it was just over-exuberance on the part of the players, after winning The Football League Trophy. However, that is still little excuse," a spokesman said.

"League clubs are working hard to encourage more families and more young supporters to matches and it is important that players recognise their wider responsibility to the game when they are in these situations."

Millennium Stadium chief executive Paul Sergeant said the flag had been confiscated by league officials and was being held by stadium staff. The flag will be handed to police later on Monday.

Mr Sergeant told BBC Wales it was the first time something like this had happened at the stadium in more than 200 games and said it was "totally uncalled for".

'Dim view'

He said: "Let's not forget it was a hugely successful day. Lots of people came and enjoyed themselves and it's a pity that something like this may overshadow what was a wonderful day for everybody."

Mr Sergeant said he believed one of the stadium stewards tried to stop the flag being displayed, but could not reach the Swansea players in time.