Children in Spain are to be allowed to take walks outside for the first time in nearly six weeks from Sunday after the government bowed to pressure to go further in its plans to ease lockdown measures.

As EU leaders prepared for a summit to assess the damage Covid-19 has done to economies and agree a plan to revive them, the Spanish prime minister, Pedro Sánchez, told MPs on Wednesday that any relaxation of the rules would be “slow and gradual”.

But the government performed a U-turn late on Tuesday night on allowing children on to the streets, after it was criticised for saying they could go out only to accompany a parent going to buy food or medicine or visit a bank.

Following the backlash – including pot-banging protests on balconies – the government said children under 14 would be allowed out for walks from Sunday if accompanied by a parent. Older teenagers will be allowed out alone to buy food or medicine.

Spain has recorded 21,717 deaths in the pandemic, the third highest number in the world after the US and Italy, and has already twice extended its state of emergency, originally declared on 14 March.

“We’re living through a time of extraordinary sacrifices,” Sánchez said as he asked MPs for a new extension until 9 May. “We can’t let our guard down. We can start to think about a de-escalation scenario. But we must be prudent.”

In a further sign that the country is turning a corner, an emergency morgue set up at an ice rink in Madrid to help the city store its dead closed its doors on Wednesday. Over the course of almost a month it took in 1,146 bodies.

The UN’s special rapporteur on human rights, Philip Alston, has said government responses to the pandemic are failing people in poverty.

“The policies of many states reflect a social Darwinism philosophy that prioritises the economic interests of the wealthiest while doing little for those who are hard at work providing essential services or unable to support themselves,” Alston said. “This is a crisis that disproportionately affects poor people.”

As some Europeans – from Danes to Austrians and German to Norwegians – took their first tentative steps out of confinement, EU leaders were expected to endorse urgent spending measures and debate a massive recovery plan at a virtual summit on Thursday.

According to the European Centre for Disease Prevention and Control, about one million people in the EU have tested positive for coronavirus and more than 110,000 of them have died – more than half of the global death toll.

The pandemic has put new strains on the unity of the 27-member bloc, exposing splits between the richer north and the poorer south. But Sánchez said he expected consensus at the summit “because it is indispensable”.

Spain has proposed creating a fund of up to €1.5tn (£1.3tn) financed by perpetual debt, but the EU’s fiscally conservative northern nations, led by the Netherlands, Germany and Austria, remain keen to keep a tight rein on spending and have rejected calls from the south for joint debt – nicknamed coronabonds – to fund recovery.

“This pandemic touches all of us in every member state and in every household,” the president of the European council, Charles Michel, said in his invitation to the summit. “It knows no boundaries and calls for even more coordination and unity. It is my conviction that we must show even greater determination in overcoming our differences.”

EU institutions and nations have already mobilised about €3.3tn combined, and leaders are expected to endorse a package worth €540bn that would help pay lost wages, keep companies afloat and fund healthcare systems.

But drawing up a recovery plan that can be endorsed by the EU’s diverse array of members is likely to prove more challenging. The consensus is that it should total at least €1tn and target the economic sectors and European regions hit hardest by the pandemic.

Meanwhile, Germany has authorised its first clinical test of a vaccine on human volunteers. The vaccine has been developed by the German firm BioNTech and the US giant Pfizer.

In further developments: