More than 900 people have been killed and 3,360 others injured in the Venezuela earthquakes, according to the government, as rescuers keep searching for survivors and families wait desperately for news.

The injured are being treated in makeshift medical facilities after dozens of buildings in the country’s north were destroyed by the two quakes, including in the capital Caracas.

A senior government official said hundreds of international rescue workers have arrived in the country, with more on the way.

Two powerful earthquakes rocked Venezuela within seconds of each other on Wednesday. The second quake was one of the strongest tremors to hit the country in a century, at a magnitude of 7.5.

La Guaira, a region north of the capital, has been hit the hardest, officials said. The state is also home to one of the country’s two main ports and to Simón Bolívar International Airport in Maiquetía – the country’s main airport.

Many people are missing, and it is likely the death toll will rise as rescue efforts continue.

In La Guaira, Natacha Diaz told the BBC that her two daughters – aged 22 and 23 – were trapped under the rubble of a collapsed shopping centre, where they worked as manicurists.

“They were with their friends,” she said. “I just want them to be found. I have faith and hope that they are there.”

“I just want them back with me. They are all I have, please.”

National assembly head Jorge Rodriguez said in a state TV broadcast on Friday that the death toll had reached 920, with at least 172 people still believed to be trapped.

In La Guaira alone, at least 243 people have been rescued, the top lawmaker – who is the interim president’s brother – said.

Dozens of people have been rescued alive, which “brings us joy that they can embrace their families and loved ones”, Acting President Delcy Rodríguez said at a televised briefing on Friday.

There have been 214 aftershocks since the initial quakes, she added.

Hundreds of buildings have been damaged or destroyed, including a number of hospitals and shopping centres, Jorge Rodríguez said, adding that at least 1,000 other infrastructure sites have also been damaged.

Surviving medical facilities are said to be overwhelmed, with medics telling the BBC that even before the disaster it was difficult to treat patients.

“All our hospitals lack supplies, lack medicines, we are not able to provide medical attention to our people in a normal day,” doctor Pedro Javier Fernandez said.

“Now with this tragedy, the emergency is even bigger and it’s more difficult to face than in other countries,” he added.

There are reports of rescuers pulling people out of collapsed buildings with their bare hands, as disrupted communications, damaged roads, and a lack of resources made the initial emergency response difficult.

A UK military flight carrying British search and rescue teams, dogs and drones left RAF Brize Norton in Oxfordshire on Friday, bound for Venezuela.

The flight is carrying specialists from 14 UK fire services, led by Merseyside Fire and Rescue.

Other countries, including the United States, the Netherlands, Mexico and Switzerland have sent teams. The US has also announced the deployment of warships and transport planes as well as $150m (£113m) in aid.

A BBC reporter in Caraballeda, in La Guaira state, has seen heavy machinery arrive to begin the task of removing rubble.

Volunteers lift a metal gate as they search through debris on the rubble of collapsed buildings in Catia La Mar

International rescue workers already on the ground have seen “horrific damage”, the secretary general of the Norwegian Refugee Council said.

Venezuela was ill-prepared and vulnerable in an emergency situation because of its already “crumbling infrastructure” following decades of underinvestment, Jan Egeland told the BBC.

Venezuela has experienced more than a decade of intense economic crisis, which has led to deteriorated living standards in the oil-rich country.

Earlier, the UN’s humanitarian chief Tom Fletcher said the disaster “needs an international global response and we’ll co-ordinate that and we will deliver”.

“I want people to know in Venezuela that help is coming,” he said.

Military personnel are distributing aid to the areas worst hit

One case that boosted morale across Venezuela is the rescue in La Guaira of three young siblings, who emerged from the rubble covered in dust and debris, footage broadcast on state television showed.

“Come here, my child, come here,” a man says to the first child as he emerges alive from a gap between chunks of concrete.

A girl then comes out, as the man asks her: “Are you siblings?”, to which she replies: “Yes, there are three of us.”

Shortly afterwards, with a little more difficulty, the third sister emerges, sobbing and covered in dust from head to toe.

Tributes are being paid to those who died. The wife of Venezuelan footballer Héctor Bello was killed while saving their daughter, according to his social media and local news.

Bello wrote on Instagram that “his precious love”, named by Venezuelan news outlets as his wife Andrea, saved the life of their toddler during the quakes.

“I’ll tell her the story of how you saved her, my love – how you gave your own life for our daughter, how you were a brave woman who never abandoned her, even as you took your last breaths,” Bello wrote in one post.

One Portuguese national and two Brazilian citizens were also among those killed, their governments confirmed.

Four Spanish nationals were also among the dead, with 106 still unaccounted for, Spanish media reported, citing its foreign ministry.

Venezuela’s Interior Minister Diosdado Cabello said multiple states had been affected by the twin quakes. In Caracas, the worst-hit areas were the neighbourhoods of Los Palos Grandes and Altamira.

The government said aftershocks had largely affected the country’s northern coastline, including La Guaira, Aragua, Carabobo and Falcón.

Leopoldo Lopez, a Venezuelan opposition leader living in exile in Spain, told BBC News the devastation has been “huge” and people were in “shock”.

He said that “unfortunately, we are seeing a parallel collapse of the infrastructure, and also the incapacity of the state to provide timely rescue support for the people in the devastated areas”.

However, there has been “tremendous support by the civil society in Venezuela”, he added.

This natural disaster has hit at a time of great uncertainty for Venezuela.

Less than six months ago, Nicolás Maduro, the left-wing leader who had ruled the country since 2013, was seized by US forces in Caracas before being flown back to New York to face drug-trafficking charges.

Maduro’s ally and former vice-president, Delcy Rodríguez, took over running the country, to the frustration of opposition supporters who had hoped the Trump administration would put opposition leader María Corina Machado in charge.