Spain's coronavirus death toll overtook that of China on Wednesday, and has risen to 4,089 after another 655 people died, health officials said on Thursday.
Meanwhile, Madrid announced a multi-million-euro deal with Beijing for critical supplies.
The spike in fatalities means that across the globe, only Italy – with 7,503 deaths – now has a higher death toll than Spain.
In China, where the virus emerged late last year, the Covid-19 epidemic has claimed 3,281 lives. However, doctors and China watchers in the US and elsewhere have been increasingly sceptical about figures released by Beijing. A report on Thursday suggested about 43,000 cases may have been left off China's statistics.
The latest figures were announced as Spain entered the 11th day of an unprecedented lockdown to try and rein in the deadly coronavirus outbreak that has now infected 56,188 people, the health ministry said.
Deputy Prime Minister Carmen Calvo, who has been in hospital since Monday, has tested positive for the virus and is improving, the government said. And two other ministers in Prime Minister Pedro Sanchez's government are infected.
Health system on brink of collapse
The surge in numbers has brought the medical system to the brink of collapse, with Spain struggling with a lack of medical supplies for testing, treatment and the protection of frontline workers, and a growing number of cases among healthcare personnel with more than 5,400 infected.
To address the shortages, Health Minister Salvador Illa said the government had inked a major deal with China.
Worth some 432 million euros ($467 million), the deal will cover 550 million masks, 5.5 million rapid test kits, 950 respirators and 11 million pairs of gloves, he told a televised news conference.
"We have secured entire production chains (in China) which will be working solely for the Spanish government," he said.
The supplies will be delivered "on a staggered basis, every week, with the first – a major delivery – arriving at the end of this week," he said.
He also said Spain would continue producing its own materials on a national level.
NATO help sought
The announcement came a day after Spain's armed forces asked NATO for humanitarian assistance to secure supplies to help curb the spread of the virus both in the military and in the civilian population.
The request specified 450,000 respirators, 500,000 rapid testing kits, 500 ventilators and 1.5 million surgical masks.
Despite the national lockdown imposed on March 14, which is to be extended until April 11, both deaths and infections have continued to mount, with officials warning this week would be particularly bad.
"We are approaching the peak," the ministry's emergencies coordinator Fernando Simon said in announcing the figures.
Health authorities are hoping it will soon become clear whether the lockdown is having the desired effect.
The Madrid region has suffered the brunt of the epidemic with 17,166 infections – just under a third of the total – and 2,090 deaths, or 51% of the national figure.
Madrid mayor Jose Luis Martinez Almeida warned the coming days would be "complicated" "psychologically" for the entire city.
Ice rink becomes morgue
With hospitals on the brink of collapse, troops have set up a massive field hospital in Madrid's vast IFEMA exhibition centre which currently has 1,500 beds but which could be expanded to take in up to 5,500 people – making it the largest hospital in Spain.
And with the city's funeral services overwhelmed, officials have commandeered the Palacio de Hielo ice skating rink to serve as a temporary morgue.
In a separate development, unions have been up in arms over a decision by Airbus to resume production in Spain, despite the outbreak, saying it endangered workers' lives.
So far, a total of 138 employees have tested positive for the virus with hundreds more in quarantine, but the European plane-maker resumed production on Monday, prompting unions to call an indefinite strike.
'Worst since civil war'
Prime Minister Pedro Sanchez, whose wife is infected with the virus, has said this is the country's most difficult moment since its 1936-39 civil war.
"Only the oldest [people], who knew the hardships of the civil war and its aftermath, can remember collective situations that were harsher than the current one. The other generations in Spain have never, ever had to face as a collective something so hard,” he said when he imposed the state of emergency on March 14.
Spain's demographics partly explain why it has been one of the worst-affected nations.
The country has one of the longest life expectancies in Europe and the pandemic has taken a high toll on its large elderly population, who are especially vulnerable to the disease.