The deputy first minister has called for universal testing across all care homes in Northern Ireland.
Michelle O'Neill said there should be a regular programme of testing for all residents and staff in residential homes.
She was speaking after new figures showed that almost half of all Covid-19-related deaths were in care homes.
Up until May 1, a total of 516 deaths involving Covid-19 were reported. Of these, 253 took place in hospital, while 232 were in care homes, four were in hospices and 27 were at residential addresses or other locations.
[ READ MORE: Coronavirus: 62% of deaths in one week were in care homesOpens in new window ]
The 236 deaths in care homes and hospices involved 66 separate establishments.
Ms O'Neill said the figures demonstrate that Northern Ireland is on a knife's edge.
"Behind all those figures are families who've lost a loved one and we need to realise that as it drives home the message why we're asking people to continue doing what we're doing for the next three weeks," she said.
"It demonstrates further to me that we're making a difference, the things that people are doing are making a difference.
"By and large, people have been absolutely first class in responding and following the public health message by staying at home, and only going out whenever they have to.
"We need people to keep on doing that because we still have this battle on our hands, and ultimately it's always about saving lives, and the more and more we move around, the more and more diseases spread."
She said that the figures also expose the "serious battle" within care homes.
"It means that no stone must be left unturned in supporting care homes right now and supporting the staff and supporting the residents.
"If you're sitting at home and one of your loved ones is in the care home, you can understand your anxiousness, you can understand your fear.
"We need to make sure that absolutely everything that needs to be done to support care homes right now is done, and I think there's a further step that's required in terms of care homes, and I believe that should be universal testing.
"There should be a regular programme of testing for all residents and staff and our care homes right now.
"I think that would help to be able to identify the virus and actually allow speedy action to be taken."
