Everton's clash with Manchester City at Goodison Park has been postponed after 'a number' of positive coronavirus tests within the City team.
The club have now confirmed that 'a number' of new cases, in addition to those already confirmed, have caused Monday evening's fixture to be re-arranged.
Two staff members also previously tested positive.
A club statement reads: "Manchester City can confirm that this evening’s Premier League fixture at Everton has been postponed.
"After the latest round of Covid-19 testing, the club returned a number of positive cases, in addition to the four already reported on Christmas Day.
"With the security of the bubble compromised, there posed a risk that the virus could spread further amongst the squad, the staff and potentially beyond.
"Based on strong medical advice the Premier League, in consultation with both clubs, have decided to postpone the fixture.
"All positive cases involving players and staff will observe a period of self-isolation in accordance with Premier League and UK Government protocol on quarantine. The first team training ground at City Football Academy will close for an indeterminate period, with the squad and associated bubble undergoing testing before any decision is made for training to resume.
"Everyone at the club wishes all of our colleagues a speedy recovery ahead of their return to work, training and competition."