Berlin, May 4 : Bundesliga club Borussia Dortmund has informed that all members of the professional squad and staff have tested negative during the first series of coronavirus test . "Borussia Dortmund has put its professional squad and members of staff through a first series of coronavirus tests. These tests did not reveal a single positive case," the club said in a statement. The club added that "further tests will follow" to ensure the largest possible degree of certainty. "BVB will do everything in its power to ensure that there are no ill persons involved in training operations and that there are no ill members of staff working with the team," it said. Earlier, three players of FC Koln tested positive for novel coronavirus, thus raising questions over the safety behind restarting the football season in May. "Three people tested positive, all are symptom-free. After an assessment of the cases by the responsible health authorities, the three people who tested positive will go into a 14-day quarantine at home," FC Koln said in an official statement on their official website on May 2. "FC Koln will not confirm any names out of respect for the privacy of those affected. FC Koln's training can continue as planned, according to the hygiene and infection control measures that have been in place since April 6th in group training," it added. The news comes amid times when Bundesliga chiefs want to restart the current campaign, with a proposed restart date of May 16 being mooted Â? although a decision on this date will be decided this Wednesday. The German football season was halted on March 13 due to the coronavirus pandemic. /IANS