In all, up to 6.8 million people could be impacted by Wednesday’s emergency, based on the latest available population and damage projections, according to the UN agency for migration, IOM.

More than 41,000 people have also been reported missing through an online portal.

And amid reports that rescuers are digging with their bare hands in some quake-hit centres, people “are still terrified to re-enter what were their homes or other structures” and need help, reported UN-partner the International Federation of Red Cross and Red Crescent Societies (IFRC).

“People left everything and nothing is functioning as it should or as it has in these areas. And so, just ensuring that people can literally survive with those essentials is our priority on the ground,” IFRC spokesperson Loyce Pace, Regional Director for the Americas, told journalists in Geneva, via video from Panama City.

Many medical needs are critical. “The overriding priority is to urgently provide lifesaving health care and rescue as many people as possible, because the first hours, as you know, are critical to saving lives,” said Dr Ciro Ugarte, Health Emergencies Director for the Pan American Health Organization (PAHO), the Regional Office for the UN World Health Organization (WHO).

Dr Ugarte described medical teams under pressure to triage mass casualties and provide trauma care for broken bones, burns and other injuries associated with buildings collapsing, particularly in areas where search and rescue operations are ongoing.

The senior medic noted in addition that access remains “very difficult” for all teams working on the ground and particularly those in the health sector, making it difficult to make a thorough assessment of the situation. "We have been struggling to reach all those health facilities," he explained.

In addition to emergency medical care, people “who have lost everything” need temporary shelter, safe water, sanitation, healthcare, protection and essential relief items, said Zoe Brennan from the UN migration agency, IOM. Later, the recovery will need to be sustained “to help families rebuild their homes, restore livelihoods and recover with dignity”, she insisted.

Aid agencies highlighted how the earthquakes hit an already vulnerable country; millions of nationals live abroad after escaping a longstanding economic crisis and human rights violations that have been the subject of an ongoing Human Rights Council investigation.

Confirming an internet blackout in Venezuela, the UN human rights office, OHCHR, said that “pre-existing restrictions” remained in place in the first few hours after the earthquakes.

“We call, as we've called before, to adopt measures to safeguard the digital space and guarantee the right to information and freedom of expression and access to digital media in Venezuela,” said OHCHR spokesperson Marta Hurtado.