One senior player and one academy player at Ulster have tested positive for coronavirus.
Training was stood down for the day and both players are self-isolating.
Ulster are due to play Ospreys at Liberty Stadium in the Guinness PRO14 on Saturday.
Further testing of players and staff will take place on Thursday.
Earlier this week, Munster also suspended training due to one confirmed case and six possible close contacts.
The Northern Ireland Department of Health reported 828 new cases of COVID-19 in the Six Counties inside the past 24-hours, and one additional death.
The Department of Health #COVID19 dashboard has been updated with latest data.
828 individuals have tested positive for COVID-19 in the past 24 hours. One death has been recorded.https://t.co/YN16dmGzhv pic.twitter.com/GkexiOINEN— Department of Health (@healthdpt) October 7, 2020
The numbers in Northern Ireland have been a major concern, with infections causing both the Armagh and Fermanagh GAA county boards to suspend activity in recent days.
Ulster Rugby Medical Director Michael Webb said, "We will continue to work closely with the Public Health Agency and the IRFU to follow all of the necessary public health advice and assist with the contact tracing process as required, as well as provide support to the individuals involved."
Ulster statement:
The latest round of PCR testing, which was carried out yesterday, has returned a positive result for one senior player and one academy player at Ulster Rugby. These players, who are currently asymptomatic, are now self-isolating in-line with public health protocols.
The Public Health Agency (PHA) has been informed, and its contact tracing process has started. Six close contacts have been identified through this process at this stage – five players and a member of the support staff. As a precautionary measure, all group training at senior and academy level has been suspended until further notice.
Ulster Rugby Medical Director, Michael Webb, said: “Following confirmation of two players testing positive, our priority continues to be the health and safety of our players and staff, so we have acted quickly with a number of measures, including standing down training from today, and asking those who have tested positive to self-isolate immediately.
“We will continue to work closely with the Public Health Agency and the IRFU to follow all of the necessary public health advice and assist with the contact tracing process as required, as well as provide support to the individuals involved.”
Further PCR testing of players and staff is due to take place tomorrow.