Italy has recorded its single biggest leap in coronavirus deaths, announcing that 969 people have died from Covid-19 in the past 24 hours.

Seemingly dashing hopes that the rate of infection might be flattening there, Italy also became the second country to overtake China in terms of the number of infections, reaching 86,498 cases. That included 66,414 current infections, up 4,401 from Thursday.

On Thursday the US became the country with the largest infection caseload, with 93,000 reported.

An extension of Italy’s coronavirus containment measures is inevitable, the country’s supreme health council (CSS) said on Friday. “We are not in a markedly declining phase, but in a phase, albeit encouraging, of containment,” said the CSS head, Franco Locatelli.

Spain, another of Europe’s hardest-hit countries, recorded 769 deaths in 24 hours, bringing its death toll to 4,858. Authorities in the country withdrew 9,000 Chinese-made coronavirus testing kits from use after it emerged that they had an accurate detection rate of just 30%.

Countries around the globe have been turning in increasing numbers to their militaries to assist with the escalating coronavirus pandemic. As officials around the world warned that their health systems were being overwhelmed, more countries joined China, Italy, Spain and the UK in deploying their armed forces to help during a pandemic that has placed more than a third of the world’s population under various forms of lockdown.

Facebook Twitter Pinterest Soldiers escort a homeless woman to a gathering point in Johannesburg, South Africa, on Friday. Photograph: Michele Spatari/AFP via Getty Images

Australia, which is introducing an enforced quarantine by midnight on Saturday for citizens returning from overseas, announced that it would use the Australian Defence Force to check on people who have already been instructed to self-isolate. The prime minister, Scott Morrison, said everyone arriving by plane would be detained in a hotel in the city of their arrival for two weeks.

Israel also announced that it would be deploying its army to assist police on street patrols to enforce a lockdown. About 500 troops will join police from Sunday to help “in patrolling, isolating and securing certain areas, blocking routes, and additional similar assignments”, the military said in a statement.

The tightened lockdown is in addition to the requirement for citizens to stay within 100 metres of their home and sanctions for those defying rules.

In South Africa, which imposed a lockdown this week, the president, Cyril Ramaphosa, ordered the military to be deployed to support the police in enforcing the restrictions.

Switzerland, where infections have topped 10,000, has turned to army medical units to help hospitals handle the virus and other units to secure the border, while Iran, which recorded another 144 deaths from the coronavirus on Friday, said its military had completed work on a 2,000-bed field hospital in an exhibition centre in Tehran.

The pandemic has spread to most parts of the world, triggering widespread secondary effects affecting both economies and wider social resilience. In the US, 3.3 million people registered as unemployed last month.

As Russia, Indonesia and South Africa all passed the 1,000-infection mark, India launched a massive programme to help feed hungry day labourers after a lockdown of the country’s 1.3 billion people put them out of work.

The stay-home order for India affected rickshaw drivers, fruit sellers, cleaners and others, forcing the government to announce a 1.7tn rupee (£18bn) stimulus to deliver monthly rations to 800 million people.

An increasing number of global cities have warned that their hospitals are at, or fast approaching, saturation point.

The head of the French Hospital Federation, Frédéric Valletoux, said on Friday that a rise in coronavirus patients meant hospitals in and around Paris would be at capacity within 48 hours, and the growth rate of infections is expected to continue into April.

Facebook Twitter Pinterest Indian soldiers on patrol in Delhi during the lockdown. Photograph: Manish Swarup/AP

In the US, New York state has emerged as the hotspot of the country’s outbreak, reporting 100 more deaths in one day. The governor, Andrew Cuomo, said the number of deaths would increase soon as critically ill patients who had been on ventilators for days succumbed.

At New York City-area hospitals on the frontline of the outbreak, workers are increasingly concerned about the ravages of the illness in their ranks, and that the lack of testing and protective gear means it is not a question of if they get it, but when.

“Our emergency room was like a Petri dish,” said Benny Mathew, a nurse at Montefiore medical centre, who added that he had Covid-19 and was worried he could infect his wife and two daughters.

“I’m angry. We could have secured enough personal protective equipment months ago. It was happening in China since December,” he said. “But we thought it was never going to happen here.”