A five-year-old child with underlying health conditions is among those with coronavirus whose deaths were reported in the past day, Cabinet Office Minister Michael Gove has said.
The latest figures show 4,313 people with the virus have now died in the UK – up by 708 on Friday’s figure.
Mr Gove said hundreds of ventilators were being manufactured every day and more had been sourced from abroad.
People have been warned to stay at home despite the warm weather this weekend.
Speaking alongside Mr Gove at the government’s daily briefing, NHS England medical director Stephen Powis said: “The sun might be out, but that does not mean you should be out.”
He said there is some evidence that social distancing measures are reducing transmission, and that the latest figures suggested new cases had begun to “stabilise”.
However, he stressed that there was “no room for complacency”.
During the briefing, Mr Gove paid tribute to one of the youngest victims of the outbreak.
“Our thoughts today are also with the family of the five-year-old with underlying health conditions who has tragically died,” he said.
By Robert Cuffe, BBC News Head of Statistics
The recent trends in deaths (doubling roughly every 3.5 days) would have predicted about 800 deaths today.
Remember that doubling every few days means that we should expect to see record new highs regularly.
Scientists remind us to look for evidence that the growth is slowing down – the first step on the journey to falling numbers of deaths.
So, compared to that projection, there is a potential silver lining to these figures – if the pattern continues.
But one day of below-trend growth is far too soon to know for sure.
It takes over three weeks from infection to death to being reported in these figures.
So while we can hope to see the effects of pre-lockdown social distancing soon, it will take longer for the effect of the lockdown, announced on 23 March, to become apparent.
There are now 41,903 confirmed cases in the UK, the Department of Health said.
The latest deaths in the UK include a further 46 people in Scotland, 13 people in Wales and eight more in Northern Ireland. There were 212 deaths in the Midlands, more than in London, where there were 127.
Mr Gove said seven healthcare professionals have now died.
Prof Powis said people were adhering to social distancing measures, and that public transport use remains “extremely low”.
School attendance was down as low as 2%, Mr Gove added.
However, Prof Powis added that people must “resist the temptation” to go out in the warm weather. Brighton and Hove City Council tweeted on Saturday that too many people were meeting up with friends on the seafront, making social distancing “impossible”.
Also in the briefing, Mr Gove said that ventilators – in addition to those being made in the UK – had been sourced from abroad, including 300 that arrived from China on Saturday.
He branded conspiracy theories spread on social media blaming new 5G masts for the spread of Covid-19 “dangerous nonsense”.