Image copyright PA Image caption DJ Campbell is one of the six men originally arrested in December

Seven players from Football League clubs in north-west England have been arrested in connection with alleged spot-fixing in matches.

The footballers are all aged between 18 and 30, the National Crime Agency said.

Six other men originally arrested in December on suspicion of involvement in spot-fixing, then later bailed, have been re-arrested, the agency added.

All 13 are currently being interviewed by police over allegations of bribery and money laundering.

Spot-fixing is where a player corruptly influences a specific element of a match, for example by intentionally getting a yellow card or conceding a corner, without trying to fix the final score.

Match-fixing, specifically spot-fixing, has become one of the biggest threats facing the integrity of sport Sallie Barker, Sport and Recreation Alliance

The NCA said: "The investigation began following receipt of material from the Sun on Sunday. It remains ongoing and we cannot provide further detail at this stage."

The six original suspects - including former Premier League player DJ Campbell - had been bailed to return on 8 April after their arrests last year.

They were re-arrested following new evidence, the NCA said.

Blackburn Rovers striker DJ Campbell, former Oldham Athletic winger Cristian Montano and four others who have not been named were arrested after allegations were made in the Sun on Sunday.

Both players named denied any wrongdoing at the time.

The newspaper also published allegations that former Portsmouth player Sam Sodje had told an undercover reporter that he could arrange yellow and red cards in exchange for cash.

'Liaising with authorities'

A Football League spokesman said: "The Football League has been made aware that a number of arrests have been made in relation to an ongoing police investigation.

"We will provide our full co-operation to the relevant authorities."

In a statement, the Football Association said: "The FA has been made aware of developments in relation to an ongoing NCA investigation, including a number of further arrests.

"We are liaising with the authorities in relation to these allegations."

Preston North End football club confirmed it had been contacted by the NCA as part of the spot-fixing investigation.

In a statement, the club said: "There are no suggestions that any offences that might have occurred involved match-fixing.

"None of our employees have been charged with any offence at this time and until or unless this position changes we will be taking no further action nor making any further comment."

The Sport and Recreation Alliance, an umbrella group for sports bodies, said it was working with sport organisations to help them protect themselves against match-fixing.

Its chief executive Sallie Barker said: "Match-fixing, specifically spot-fixing, has become one of the biggest threats facing the integrity of sport."

She added: "Sport can't afford to be complacent about the risks posed by corrupt and illegal betting."