The German soccer league reported 10 positive tests for the new coronavirus among 36 clubs in the Bundesliga and second division on Monday.

The DFL said that 1,724 tests for COVID-19 were carried out over two rounds among players, coaches, physiotherapists and other staff. The tests were part of the league’s hygiene concept as it bids to restart competitive games some time in May. It said teams will also undertake a “a mandatory training camp under quarantine conditions before a possible continuation.”

Only four possible cases had been reported already. Cologne on Friday said it had three positive cases, while second-division Stuttgart reported one “inconclusive result” from a person on Sunday. Reportedly a player, he was separated from his colleagues and placed in quarantine for 14 days.

Of the 18 Bundesliga teams, only Leipzig, Augsburg and Borussia Mönchengladbach declined to give details of their test results. The DFL warned clubs in an email from director Ansgar Schwenken late Sunday not to share any more details of results with the media.

Cologne faced criticism from within from midfielder Birger Verstraete, who told Belgian TV station VTM that it was “not entirely correct” that he had not been in contact with the affected individuals.