The deaths of 15 people from Covid at a Llangollen care home is a "very sad story", the first minister has said.
There have been 56 cases of coronavirus among residents at Llangollen Fechan Care Home, with 33 staff also testing positive.
The movement of staff and residents is being restricted to help reduce transmission.
An incident management team is investigating the cause of the outbreak.
At Friday's coronavirus briefing, First Minister Mr Drakeford said the rules around care homes were much stronger now than they were in the spring because of a better understanding of how Covid-19 spreads.
"But once coronavirus is in a care home it is there with a group of the most vulnerable people with underlying health conditions, elderly people, and it's a virus that just attacks people in that deadly way," he said.
"A lot of help is being provided both to that care home in Llangollen, where there is that very sad story today, but other care homes as well, to make sure that all those basic things the care home itself has to take responsibility for are being done in the best possible way."
Mr Drakeford also explained that discussions are continuing over the use of the latest testing equipment and that care home staff and residents "are very much part of that conversation".
Nicola Stubbins, co-chairwoman of the incident management team, involving Denbighshire County Council, Public Health Wales and Betsi Cadwaladr University Health Board, said: "We have been working together to investigate a number of cases of coronavirus in staff and residents at Llangollen Fechan Care Home in Llangollen.
"We would like to assure all concerned that control measures have been put in place working jointly with the care home, including limiting the movement of staff and residents to reduce transmission.
"Our thoughts and condolences are with all affected and we remain committed to working together to address the situation.
"Anyone who meets the definition of a contact will be contacted as a routine part of the Test, Trace and Protect process and provided with additional advice for themselves, their household and other contacts."