LA GUAIRA, Venezuela (AP) – Venezuelans took the search for missing loved ones into their own hands Friday in the aftermath of back-to-back earthquakes, citing the scarcity of government rescuers, as the human toll of the disaster climbed to at least 920 dead and more than 3,300 hurt.

Citizens digging through the rubble of their homes said they have seen few state rescue teams in the areas hit hardest by the devastating 7.2 and 7.5 magnitude quakes that struck late Wednesday, despite authorities projecting an image of a robust government response.

The lack of help compounded families’ desperation as the pressure to find buried survivors increased with each passing hour. The South American nation on Friday marked nearly two days since the disaster. Aid agencies consider the first 48 to 72 hours to be a crucial time frame to retrieve people alive, though that period increases if they have access to food and water.

Meanwhile, a broad international aid effort accelerated, with more than two dozen rescue teams from around the globe arriving in Venezuela or due to arrive there soon.

“Each person saved is a miracle,” said Jorge Rodriguez, the president of the country’s National Assembly. “We are not going to hide absolutely anything about the magnitude of this tragedy.”

Anxious Families Wait to See If Their Relatives Survived

Desperate families across northern Venezuela searched in the ruins of buildings for family members and whatever remained of their lives.

Nazareth Jimenez sobbed into the shoulder of a loved one as she watched neighbors try to cut through slabs of concrete with hammers and power tools in a building reduced to a mountain of debris. “How are we going to get them out of there?” she murmured.

She was in the northern state of La Guaira, just north of the capital of Caracas, where some of the worst destruction unfolded. Mr. Jimenez was wracked with anxiety as she waited to see if her siblings, nephews, nieces and friends would emerge from the debris alive.

“We’re making a call for help to governments of countries across the world,” she said, pleading for machines that would be capable of moving collapsed structures. “There are still people alive in there.”

Government forces distributed food and water to survivors in La Guaira as acting President Delcy Rodriguez said her government was “working tirelessly” to mount a full response. She welcomed the arrival of rescuers and humanitarian aid from all over the world. She said La Guaira had been militarized and that more help was on the way, even as residents said it was just a fraction of the aid they needed.

The disaster poses a huge challenge for Ms. Rodriguez, the former vice president who took office in January after the capture and removal of then-President Nicolas Maduro by the United States. Venezuela has been facing economic disarray for more than a decade and many people reject the legitimacy of the political movement Ms. Rodriguez represents.

The number of dead was expected to climb, with thousands of people reported missing. Venezuelan authorities said Friday afternoon that they had rescued 243 people.

Quakes Leave Millions of People Reeling

The International Organization for Migration said that up to 6.76 million people in Venezuela could be affected by the quakes, some 2 million of them in Caracas alone. Loyce Pace, the International Red Cross’ regional director for the Americas, said “people are still terrified to reenter what were their homes.”

Buildings across northern Venezuela were reduced to skeletons, with furniture hanging out of windows and helicopters circling overhead.

Desperation started to sink on Friday as many families still had not found their missing loved ones, had minimal equipment for rescue efforts and continued to sleep on the street.

In Catia La Mar, a community adjacent to the country’s main airport, people swarmed a civilian pickup truck that was giving out loaves of bread and water. A soldier intervened to allow the vehicle to leave. People turned the parking lot of a pharmacy into makeshift shelter by setting up tarps, hammocks and tents.

Omar Reyes walked through the remains of what was once his home, calling out the names of wife and children. He received no response.

Around 20 family members have died. Two of his four children are buried in the debris.

“I’ve been left alone in this life,” he said quietly.

International Aid Is On the Way

Venezuela authorities said Friday that 861 international volunteers from Mexico, the U.S., El Salvador, Switzerland, Colombia and beyond were working in Venezuela. Many more from other countries were expected in the coming hours and days. The UN said 1,000 emergency responders in 25 search-and-rescue teams from across the globe were on their way.

On the country’s main highway, caravans of state forces, emergency personnel, dump trucks and heavy machinery moved in the direction of the tragedy. A civilian pickup truck carrying thin mattresses had its windows marked with “Help from Trujillo.” Venezuela’s government said it had diverted emergency services to La Guaira state.

Firefighters from the state of Tachira, which borders Colombia, were among those being deployed in La Guaira.

Firefighting Gen. Antonio Briceno said 45 firefighters and a trained dog, aptly named Rescue, expected to reach affected sites in the coming days.

“We are bringing shovels, picks, hydraulic tools, drinking water, which are needed at the site,” Mr. Briceno said.

On Thursday night, the U.S. Treasury moved to waive sanctions until October 23 to allow transactions related to earthquake relief efforts in Venezuela that would otherwise be prohibited.

Government and Rescuers Face Huge Challenges

Media reports have shared notable moments of hope, including a young man brought out on a stretcher in the San Bernardino district of Caracas to the applause of onlookers as his tearful mother said, “Leandro, I love you.”

Venezuelan TV broadcast video of a girl covered in dust and wrapped in a sweatshirt as she emerged from rubble with the help of rescuers. Caracas metropolitan rescue team head Jose Luis Nunez said she was found in a 10-story building in La Guaira that collapsed and flattened “like a pancake.”

“We want to highlight this girl’s strength, determination and will to live,” Mr. Nunez said.

The U.S. Geological Survey said both earthquakes were centered near Moron on the Caribbean coast, about 105 miles west of Caracas. The one-two punch of the quakes, combined with the shallow seismic movements, amplified the destruction, said Marcos Ferreira, a geophysicist and researcher at the Geological Survey of Brazil.