Newcastle United's training ground remained closed for a second successive day on Tuesday in an attempt to deal with an outbreak of coronavirus.
Manager Steve Bruce said on Friday that three players and one member of staff had tested positive and on Monday the training ground was shut.
After a round of tests on Sunday, further cases were identified and players have since remained at home.
The Magpies are due to play Aston Villa in the Premier League on Friday.
It is not clear if the team will return to their training base on Wednesday.
The Premier League's coronavirus protocols say the game would only be postponed if Newcastle had fewer than 15 players available for the game, but each case will be determined individually.
After his team's 2-0 win at Crystal Palace last Friday, Bruce admitted the situation had been "difficult to manage".
Midfielder Isaac Hayden missed that match with illness, while captain Jamaal Lascelles, winger Allan Saint-Maximin, forward Andy Carroll and defender Emil Krafth were reported injured.
The Premier League has reported 10 new cases of coronavirus this week, up to Sunday, but has not said at which clubs they were diagnosed.
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