Manchester United will not say whether they were forced to shut down their system when they demanded a ransom due to a cyber attack on the club last week.
United said Friday that they had been hit by a “sophisticated” attack, and that the matter was still hampered.
The Daily Mail reports The hackers claimed “millions of pounds”.
United said it could not identify the motive for the attack and rejected the offer, saying the attackers still had control of the systems.
Of the club Champions League match against Turkey’s Istanbul Basaksehir Tuesday went ahead as planned, although some administrative issues surrounding the entrance to Old Trafford in the case of attendees need to be changed.
Although the issue is causing major disruption to the club, including emails that have not been working throughout the week, it is understood that investigations and recovery work are at an advanced stage to ensure their internal systems are safe.
The National Cyber Security Center, which provides guidance to organizations that have been attacked, is involved and has advised the club.
United said in a statement: “Following the recent cyber attack on the club, our IT team and external experts have secured our networks and conducted forensic investigations.
“The attack was disrupted by nature, but we are not currently aware of any fan data compromises.
“The critical systems needed for matches at Old Trafford were secure and the games went on as usual.
“The club will not speculate on who may be responsible for the attack or the motive behind it.”