A magnitude 6.6 earthquake struck the southern Philippine island of Mindanao on Friday, the Philippine state seismology agency Phivolcs said.

The quake that struck 90 km southwest of Balut Island in Davao Occidental province had a depth of 10 km, Phivolcs said, adding that aftershocks were expected, but there was no threat of a tsunami.

The powerful quake comes weeks after the magnitude 7.8 earthquake that also struck Mindanao on June 8.

The death toll from the June 8 quake has risen to 81 with more than a thousand people injured, according to the country's civil defence agency.