Six people from three clubs have tested positive for coronavirus the English Premier League confirmed in a statement on Tuesday.
The positive tests are from the first phase of mass testing covering a total of 748 tests from the 19 clubs tested at the weekend.
The remaining club did their tests on Tuesday so will be included in Saturday’s results.
It is unclear whether the positive tests include players, non-playing staff or a combination of both.
The unnamed players or staff who have tested positive will now self-isolate for seven days and cannot attend the clubs’ training ground.
Clubs are expected to take part in a second phase of testing later this week with the results of the second round of testing due to be published on Saturday.
“The Premier League can today confirm that on Sunday, May 17 and Monday, May 18, 748 players and club staff were tested for COVID-19,” a Premier League statement read on Tuesday.
“Of these, six have tested positive from three clubs. Players or club staff who have tested positive will now self-isolate for a period of seven days.
“The Premier League is providing this aggregated information for the purposes of competition integrity and transparency. No specific details as to clubs or individuals will be provided by the League and results will be made public in this way after each round of testing.”
Premier League clubs voted to start non-contact training from Tuesday with a view to resuming the season on 12 June.
However, there is now an expectation this will need to be pushed back.
Professional football in England has been suspended since 13 March because of the Covid-19 pandemic, with 92 fixtures of the current topflight campaign remaining.
The German Bundesliga became the first major European football league to restart after the coronavirus shutdown when it resumed behind closed doors over the weekend.