A director of public health has warned that his Welsh health board could see catastrophic levels of coronavirus cases during Christmas if infections in the area continue to rise.
Dr Keith Reid from Swansea Bay University Health Board said he feared only another lockdown in Wales before the Christmas period would be enough to save the local system from being "overwhelmed" if rates continued to rise.
His comments came as Welsh Health Minister Vaughan Gething said eight local authority areas in Wales now had Covid-19 rates of more than 400 cases per 100,000 people, with cases rising in 19 out of 22 areas.
Wales also now has its highest ever number of Covid-19-related patients in hospitals with 1,800 in total, as well as the worst infection rate in the UK, just four weeks after the end of the country's 17-day firebreak.
On Monday, Dr Reid said: "We are at a critical stage. Infection rates are at record levels and we all need to play our part to bring this situation under control and quickly.
"If infections continue to rise at the current rate then without another lockdown before Christmas the local system will be overwhelmed."
Neath Port Talbot, covered by the Swansea Bay health board, has the highest infection rate in Wales with 622 cases per 100,000, with Swansea not far behind with 446 cases per 100,000.
Back in September, there were just 56 cases per 100,000 for Swansea and just 38 cases per 100,000 for Neath Port Talbot.
Dr Reid called on the public to keep their distance from others and "do the right thing" in order to avoid bringing the health system to its knees.
"I don't want to be standing here within the next fortnight telling people the spread of the virus is out of control, that too many people are dying needlessly and health and social care workers can't cope for much longer," he said.
"It is a big thing to ask at this time of year when, after the kind of year we've had, we all want to be together with our friends and family. But my appeal is – on behalf of doctors, nurses and social care workers who have been at full stretch for so long – please stop and think.
"We have a chance to stave off a potential catastrophe. But we all have a role to play."
Dr Reid said he believed that people mixing with others inside homes, in the street, and at work was the driving force behind the rise in cases.
Director of social services at Swansea council, David Howes, said demand for hospital and community services "is now becoming greater than the resources we have available to us", while its leader, Rob Stewart, said "we are in a critical time".
Rob Jones, leader of Neath Port Talbot Council, called on the public to "pull together and resist the temptation for social mixing".
At Monday's Welsh Government press briefing, Mr Gething said Wales was the only part of the UK where virus rates were not falling at the end of November.
"This reflects that there were tighter measures elsewhere in the UK – England was still within its four-week lockdown, Northern Ireland was between lockdowns and Scotland was tightening its restrictions," he said.
Tougher restrictions were introduced in Wales on Friday with hospitality businesses banned from selling alcohol and forced to close at 6pm until December 17 at the earliest.
Mr Gething said the effects of these restrictions would not be seen for weeks and it could be longer before pressure on the NHS was reduced.
"If we do not see a reduction in coronavirus admissions, we will need to consider what action we can take and may need to support the NHS as we move into the New Year, " he said.
Mr Gething said he could not rule out a second national firebreak lockdown after Christmas, saying: "Everything is on the table."
On Monday, Public Health Wales reported a further 2,021 cases of Covid-19 in Wales – the highest amount recorded for a single day – bringing the total number of confirmed cases to 91,013.
It also reported another two deaths, taking the total in Wales since the start of the pandemic to 2,711.