MANILA -- Strong aftershocks from an earthquake that has killed at least three people and a new tremor in southern Philippines are forcing thousands of residents to stay in evacuation centres, disaster officials said on Monday.

"We are scared up to now because of the aftershocks," Alex Arana, disaster agency chief of Surigao del Sur, told DZBB radio station.

His coastal province was closest to the epicentre of the magnitude 7.4 earthquake, which struck late on Saturday and was followed by aftershocks. It was also the most damaged area.

Two people died -- one as a result of falling debris and another because of a collapsed wall -- and eight were injured in Surigao del Sur, Arana said.

A pregnant woman was killed when a wall collapsed as she and her family were fleeing their home in Tagum city in Davao del Norte province.

As of late on Sunday, more than 108,000 people were staying in 115 evacuation centres in Surigao del Sur, government data show.

A magnitude 6.8 earthquake, with a depth of 1 km (0.62 mile), struck Mindanao in the Philippines in the early hours of Monday, the Philippine seismology agency reported.

It was not part of the magnitude 7.4 quake and about 1,700 aftershocks, officials said.

"We get dizzy from tremors every so often. We choose to stay here at the evacuation centre for now," Susan Clor, a resident of Hinatuan town in Surigao del Sur, told GMA television station.

Earthquakes are common in the Philippines, which lies on the "Ring of Fire", a belt of volcanoes circling the Pacific Ocean that is prone to seismic activity.