Rescue crews and volunteers have clawed through the rubble of collapsed buildings, racing to find survivors 72 hours after twin earthquakes tore through Venezuela, killing at least 1,430 people and leaving tens of thousands missing.

Experts said the first three days after such disasters are a critical window to locate people alive beneath the debris. That window ends on Sunday. “It’s just very chaotic, hot and unorganised,” said Australian firefighter Craig Demeillon, 43, who travelled alone from Miami, Florida, to La Guaira, the hardest hit area, to help. “Hopefully, there’s more people to find.”

In one of the most striking rescues, residents in the coastal area pulled a newborn alive from the ruins on Friday, about 32 hours after the magnitude 7.2 and 7.5 tremors on Thursday. A man was seen in a widely shared social media video crying as he cradled the baby.

The search effort has been hampered by restricted access to La Guaira state and the requirement that volunteers obtain safe-entry passes. “You need a permit to save lives. Just imagine,” would-be rescuer Carlos Itriago, 27, said while waiting in line for permission to enter the disaster zone. “How many lives have we already lost by now?”

The first United States military aid flights have landed in Caracas, and a naval ship is offshore as foreign search and rescue teams arrive with dogs and specialised equipment.

The United Nations says up to 6.76 million people may need shelter, safe water and medical care, warning the death toll and the number of bodies recovered are likely to keep rising as the rescue phase gives way to grim recovery.