Venezuela made a last-ditch effort Monday to find survivors as hopes were dwindling more than four days after powerful twin earthquakes struck the country, leaving at least 1,450 people dead and tens of thousands missing.

French and American rescue teams found a man and his teen son alive under the rubble Sunday in Caraballeda, a town about 40 kilometers (25 miles) north of Caracas, reported Agence France-Presse (AFP).

The rescue offered a glimmer of hope in an ongoing tragedy that has shaken a country already mired in an economic crisis, but that hope dwindled as the critical 72-hour window for rescuing trapped victims passed.

Millions more people were feared to lack sanitation and other basic needs after one of Latin America's most devastating earthquake disasters, as residents grew increasingly frustrated with the government's response to the disaster.

Some 774 buildings were badly damaged in back-to-back quakes of magnitude 7.2 and 7.5 that struck Wednesday evening, including 189 buildings that have totally collapsed, National Assembly President Jorge Rodriguez said Sunday.