Seven further arrests in match-fixing probe
Six players were originally arrested in December "in connection with an investigation into individuals suspected of conspiracy to commit acts of bribery and money laundering relating to conduct during football matches".
These individuals have also been taken back into custody.
The National Crime Agency (NCA) confirmed last year that they had begun looking into details passed to them by a national newspaper, claiming to have evidence of a player willing to arrange a yellow card in a Championship fixture in return for money.
An NCA statement, released on Thursday said: "The NCA has today rearrested the six original suspects based upon new evidence, along with a further seven footballers aged between 18 and 30 suspected of potential involvement in these offences.
"The seven men arrested in addition to the original six are from Football League clubs based in the north west of England. All 13 individuals are being interviewed at police stations across the country."
Oldham sacked midfielder Christian Montano - believed to be one of the six originally arrested - in December for a "very serious breaches of club discipline", which "constitutes gross misconduct".
Responding to the NCA's statement, the Football League confirmed they would assist in any way possible.
"The Football League has been made aware that a number of arrests have been made in relation to an ongoing police investigation," a spokesman said via the organisation's official website.
"We will provide our full co-operation to the relevant authorities. Given that it is an ongoing matter, we cannot comment further at this time."