Spain on Sunday announced 394 new deaths caused by the novel coronavirus, raising to 1,720 the official death toll in Europe's worst-hit country after Italy, a 30 percent increase over the previous day.
The number of confirmed cases of the disease rose by 3,646, or 14.6 percent, to 28,572, according to health ministry figures, with officials warning infections will rise further in the coming days.
Spanish Prime Minister Pedro Sanchez said his country's situation was now the most difficult since the 1936-39 civil war.
The outbreak in Spain, already among the harshest in the world, would continue to worsen, he warned.
"We must prepare ourselves emotionally and psychologically for very hard days ahead," he told the nation in a televised address late on Saturday.
"We have yet to receive the impact of the strongest, most damaging wave, which will test our material and moral capacities to the limit, as well as our spirit as a society," he added.
With 1,785 people being treated in intensive care units for the virus, there is mounting concern about the ability of hospitals to cope.
Health care workers accounted for over 10 percent of all confirmed cases of coronavirus, the health ministry's emergencies coordinator, Fernando Simon, said.
"This is a significant problem for our health care system," he told a news conference.
Authorities have called up 52,000 extra workers to help the country's health service as it struggles to contain the virus, including 14,000 retired doctors and nurses.
Soldiers helped move coronavirus patients on Sunday to a makeshift field hospital set up at a Madrid conference centre which is to be fitted with 5,500 hospital beds, which would make it the biggest such facility in Europe.
About 1,300 hospitals beds have so far been set up at the facility and officials plan to move over 300 patients there this weekend, the director of the field hospital, Antonio Zapatero, said in an interview with daily newspaper El Mundo.
Spain on March 14 issued lockdown orders for its roughly 46 million residents who are only permitted to leave their homes for essential work, food shopping, medical reasons or to walk the dog.
Sanchez is expected to ask parliament to extend the initial 15-day state of emergency for another two weeks.