Covid-19 case rates are continuing to rise in almost every part of Wales with the biggest jumps in Merthyr Tydfil, Bridgend and Blaenau Gwent.
The figures, for the seven days to December 17, are based on tests carried out in NHS Wales laboratories and those conducted on Welsh residents processed in commercial laboratories.
They show the number of new cases per 100,000 people in Merthyr Tydfil has risen sharply week-on-week from 926.6 to 1,299.6 - the highest rate in Wales - while in Bridgend the rate has increased from 777.3 to 1,122.1.
In Blaenau Gwent, the rate is up from 698.5 to 1,006.3.
Conwy, the one area that has recorded a week-on-week fall, saw its rate drop from 95.6 to 77.6.
Wales has by far the worst case rate of all four UK nations with the new coronavirus variant thought to be responsible for "the huge growth in cases" seen in recent weeks.
At the end of November, the seven-day coronavirus rate for Wales was 232 cases per 100,000 people but this is now 623 cases per 100,000 and rising.
A third nationwide lockdown in Wales began on December 20, with plans to relax rules between December 23 and 27 scrapped.
Two households will be allowed to meet on Christmas Day only.
Here are the latest rates, ranked from highest to lowest:
Merthyr Tydfil - 1,299.6
Bridgend - 1,122.1
Blaenau Gwent - 1,006.3
Neath Port Talbot - 964.3
Newport - 895.4
Caerphilly - 838.9
Rhondda Cynon Taf - 829.4
Torfaen - 804.6
Swansea - 747.0
Cardiff - 677.6
Vale of Glamorgan 610.8
Monmouthshire - 491.6
Wrexham - 454.6
Flintshire - 265.9
Pembrokeshire - 251.2
Ceredigion - 246.2
Powys - 224.3
Denbighshire - 145.3
Gwynedd - 81.9
Conwy - 77.6
Isle of Anglesey - 47.1
The impact of the new strain of Covid-19 on the NHS in Wales will be "profound" if cases continue to rise unchecked, the First Minister has said.
Mark Drakeford said the new variant provides "better understanding" for the large increase in cases and people being admitted to hospital in Wales from late November.
The Welsh Government took "unavoidable action" to place Wales under Tier 4 restrictions over the weekend and to change Christmas arrangements after receiving information about the spread of the variant in the country.
"Of course I wish that we had been able to give everyone more notice of these changes but, in light of the information we had in front of us, it was imperative to take swift action to prevent further harm and to save lives here in Wales," Mr Drakeford said.
He told the press conference there are more than 600 cases of the new variant in Wales but this is a "almost certainly a significant under-estimation".