The lockdown in Wales has been extended by three weeks, First Minister Mark Drakeford has confirmed in a video message.
Despite some positive signs, he said it was "still too early to change course" in the coronavirus fight.
He said lifting the stay-at-home restrictions too soon could result in more deaths.
Ministers from all four UK nations have all agreed to do the same - pushing the lockdown into May.
Welsh ministers had already announced it would be extended, but not by how long.
Foreign Secretary Dominic Raab made the same announcement for England on Thursday evening - Mr Drakeford said UK government ministers had "caught up" with his decision from last week.
Under the restrictions you may only leave home for a limited set of reasons, which include:
- To obtain essentials, such as food and medicine
- For exercise, once a day
- For work, if you cannot work from home
People who breach the lockdown can be fined by the police. In Wales they range between £60 for a first offence and £120 for subsequent offences.
Gatherings of more than two people are banned and many shops have been forced to close.
Senior ministers from Wales, Scotland, Northern Ireland and the UK government discussed the lockdown at a meeting of Cobra on Thursday.
In his video message, Mr Drakeford said each of the ministers agreed that "the current restrictions on movement to protect the NHS and so to save lives, should continue for another three weeks".
He said this was based on expert scientific analysis of the latest data on the coronavirus outbreak.
'Many lives are still at stake'
The first minister said he knew the last three weeks had been difficult for many people.
But he said: "While there are some positive signs in the data, it is still too early to change course.
"Many lives are still at stake and too many families have already lost loved ones."
Mr Drakeford added: "I am clear that we cannot risk throwing away all the sacrifices we have made here in Wales over the last few weeks by lifting the restrictions too soon.
"That could mean more deaths and, in the long run, even greater impact on people's jobs and livelihoods."
While the UK government and the three devolved governments are working together on the lockdown measures, the rules are made on a per-country basis.
The Welsh Government has its own lockdown legislation, which is broadly the same as elsewhere but has small differences, including measures on social distancing in the workplace.
Mr Drakeford told BBC Wales Today UK government ministers "have caught up" with his announcement last week that he would extend the lockdown "because they've agreed today with what I said".
Although he insisted he was "keen" to work on a "four-nation basis", he said his responsibility was to Wales first.
"I think we're always stronger in this position where we're able to work together and act together, but in the end my responsibility is to do the right thing for Wales," he added.
Opposition leaders in Wales backed the extension.
Welsh Conservative assembly leader Paul Davies said: "Based on the scientific data available, and the number of cases of coronavirus, this really is the only sensible and safe approach to take at the moment."
Plaid Cymru leader Adam Price called for assurance that the lockdown restrictions across the UK "will only be lifted when all home nations agree to it".
Welsh Secretary Simon Hart, a Conservative UK government minister, said the announcement was "to be expected".
"Everybody agrees we're not quite there yet and there's another big push required to see if we can get those numbers really under control."
Dominic Raab told the daily No 10 briefing that a review concluded relaxing the measures now would risk harming public health and the economy.
"We still don't have the infection rate down as far as we need to," he said.
The announcement came as a former consultant at Public Health Wales warned of "dramatic" long-term effects on people's health from the economic impact of the lockdown.
Prior to Thursday's announcement, Dr Roland Salmon, a retired medical epidemiologist, said: "I don't think it's clear that the lockdown has worked.
"If we see the press conferences in 10 Downing Street every afternoon, we see people looking at the graph and telling us that there are green shoots - but the green shoots never seem to quite turn into flowers."
He said when life expectancy, health inequalities and well-being are weighed up, "the health price that we'll have to pay in the future may well be more than the benefit that we are getting now".