In pictures: Race against time to save earthquake survivors in Venezuela | Stories About Earthquakes

Rescuers and volunteers have combed through the rubble of collapsed buildings, scrambling to find survivors 72 hours after two earthquakes struck Venezuela, killing at least 1,430 people and leaving thousands more missing.

Experts say the first three days after such an accident is the most important window to find people alive under the rubble. That window ends on Sunday. “It’s very confusing, hot and unplanned,” said Australian firefighter Craig Demeillon, 43, who traveled alone from Miami, Florida, to La Guaira, the worst-hit area, to help. “Hopefully, there’s a lot of people out there to find them.”

In one of the most dramatic rescues, beachcombers pulled a baby alive from the wreckage on Friday, about 32 hours after the 7.2 and 7.5 earthquakes on Thursday. A father was seen in a widely shared video crying as he put the baby to bed.

The search has been hampered by restrictions on access to La Guaira district and the need for volunteers to obtain security clearances. “You need permission to save lives.” Imagine,” lifeguard Carlos Itriago, 27, said as he waited in line to get permission to enter the disaster area. “How many lives have we already lost here?”

The first US military aid planes have arrived in Caracas, and a submarine is ashore as foreign search and rescue teams arrive with dogs and special equipment.

The United Nations says 6.76 million people may need shelter, safe water and medical care, warning that the death toll and the number of bodies recovered are expected to rise as the rescue operation progresses.