Lee Trundle pictured holding the flag bearing anti-Cardiff obscenities

It follows Trundle parading a flag with anti-Cardiff obscenities after his side won the Football League Trophy Final at the Millennium Stadium.

Defender Alan Tate was also seen holding a Welsh flag daubed with obscene words directed at Cardiff fans.

Swansea supporters have received the threatening texts, but not Trundle personally, according to police.

A spokesman for South Wales Police said they had been "made aware of" the threats and were "monitoring the situation".

During celebrations after Swansea City's 2-1 victory over Carlisle United in the final on 2 April, Trundle was also seen wearing a T-shirt with an image of a Swansea player urinating on a Cardiff shirt.

Both players have been arrested and questioned by South Wales Police, and are due to answer bail at the end of April.

The pair could also face possible professional discipline after the Football Association of Wales decided charges would be issued against both the club and the two players over the post-match events.

Although Cardiff City were not involved in the Millennium Stadium final, there is a history of tension between fans of the two south Wales clubs.

Number of complaints

After the flag incident, Swansea immediately apologised "for any distress caused" saying the players involved had been caught up "in the moment".

The club said the players had picked up articles thrown from the crowd "without realising the offensive nature of some of the items".

It said both players stressed no malice was intended.

The Football Association of Wales (FAW) said it was investigating the "insulting" images, and police arrested and then released the two players on bail.