Ten people have been killed after a seven-story under-construction building collapsed early Saturday in southwestern Cambodia's Preah Sihanouk province, local media reported, citing the Provincial Governor Yun Min.

Between 40 and 50 workers were sleeping in the construction site when the building collapsed, the governor said, adding that two excavators were being used to remove rubble in order to search for those trapped.

Four people in charge of the construction site have been detained by local police.

According to local authorities, the building was constructed on a parcel of 15 meters by 30 meters, and about 80 percent of the construction was completed.

The incident happened at about 5:00 a.m. local time in commune 4 in Sihanoukville, the National Police said on its website.

The research work and an investigation into the cause of the incident are ongoing.

(With input from Xinhua News Agency)