Jakarta - Nine people were seriously injured and many buildings were damaged when an earthquake measuring 7.4 on the Richter scale struck early Thursday off the northern tip of Indonesia's Sulawesi island, an official said.

A small island chain off Sulawesi near the Philippines was hit hardest, with houses and government buildings collapsing, said Sutiono, an official at the Meteorology and Geophysics Agency in Jakarta.

"According to the latest information, nine people were badly injured in Kabarua district," Sutiono told Deutsche Presse-Agentur dpa.

"A small island thought to be badly affected still couldn't be reached by telephone."

The agency has lifted an initial tsunami warning, he said.

The quake at a depth of 35 kilometres near the Talaud islands between Sulawesi and the southern Philippines occurred at 1734 GMT Wednesday, the US Geological Survey said.

Sixty-two aftershocks measuring as high as 5.7 on the Richter scale were recorded since the biggest quake, Sutiono said.

The Pacific Tsunami Warning Centre said that waves were possible within 100 kilometres of the epicentre. (dpa)