"The tragedy of the building collapse in Preah Sihanouk province is painful. for our nation, especially the families of those who lost" their lives, he said, announcing compensation of $10,000 each for the victims' households.
Prime Minister Hun Sen is heading to the region.
Seven people are dead and dozens missing after a partially completed building collapsed in Cambodia.
He stated on Facebook that he asked Yun Min, the governor of the Preah Sihanouk province, to resign - to which he agreed.
Cambodian Prime Minister Hun Sen on Sunday said he would take personal charge of the rescue operation as hundreds of rescuers dug through twisted metal and concrete overnight in search of survivors.
Authorities said they had detained four Chinese nationals involved in the construction.
In recent years, Sihanoukville has been transformed by the construction of Chinese hotels and casinos.
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The once-quiet fishing village of Sihanoukville has seen a remarkable Chinese construction boom driven by the need for rooms for tourists flocking from the mainland to its dozens of casinos.
Chinese investment has flowed into casinos, hotels and real estate in Preah Sihanouk province and its largest town, Sihanoukville, turning the once sleepy seaside town into a flash point for Cambodians concerned about Chinese economic penetration of their country.
The Chinese news agency Xinhua reported that Seng Loth, a spokesman for Cambodia's ministry of land management, planning, and construction, said the collapsed building had been erected without permission. Rescue workers were using saws to cut steel beams and excavators to move piles of rubble of the collapsed seven-story building. One of them, Nhor Chandeun, said he and his wife were sleeping when they heard a loud noise and felt the building vibrate and then begin falling down. They were trapped for 12 hours before rescuers found them.
"My wife and I kept calling for help", he said.
It is not clear how many people were at the site at the time of the collapse.
"We have rescued 20 so far... we still can't say exactly how many are trapped in the debris", he said, adding some may not have been at work at the time of the accident.