A rescue team searches for victims in the ruins of the Laurensius Say Port in Maumere, Sikka, East Nusa Tenggara after a magnitude 7.7 earthquake struck Flores Island.

Maumere, Indonesia - Rescuers combed through debris for survivors Saturday after a powerful earthquake struck off Flores island in eastern Indonesia, killing 20 people and sending thousands fleeing.

Rescue official Fathur Rahman told AFP at least 20 people were confirmed dead on the popular tourist island and six others reported injured.

At least two people were known to be trapped alive under rubble following the 7.7-magnitude quake, he said.

"I have never felt an earthquake this big," Yulian Juita Ekalia, who lives in Ruteng city more than 100km west of the epicentre, told AFP by telephone.