LA GUAIRA, Venezuela, June 28 (Reuters) – A father and his son were rescued alive from the rubble of a collapsed building on Sunday, four days after powerful earthquakes struck Venezuela.

Their rescue gave hope to French and American rescue teams, who are still searching for more survivors.

The two men, both weak and wearing masks, were carried on makeshift stretchers through streets covered with debris to a waiting ambulance in La Guaira, as crowds gathered nearby.

La Guaira was the area most badly affected by Wednesday’s earthquakes, which killed at least 1,450 people and left thousands missing.

The rescue operation took 12 hours. Teams used special cameras and carefully removed unstable debris to reach the trapped father and son.

“They are extremely weak after being trapped for four days. We are giving them fluids and medicines while slowly bringing them out,” a member of the French Civil Security team said.

The rescue team included members of the French Civil Security and the Fairfax County Urban Search and Rescue Team from Virginia, USA. The same team had rescued a mother and her 9-month-old baby the day before.

Before bringing the two men out, rescuers prepared intravenous drips and cleared away debris. Other rescue workers continued searching the rubble for signs of life.

At least 33 people were rescued over the weekend, but tens of thousands are still missing, increasing fears that time is running out.

Experts say that after 72 hours following an earthquake, the chances of finding survivors under the rubble decrease sharply.