Three workers were dead, seven injured and an unknown number of others were buried after a scaffold and a concrete roof collapsed at a construction site in east China's Anhui Province Tuesday, said local authorities.

Injured workers had been sent to hospital, where three of them died, said Zhang Min, an official of the publicity department of Wuhu municipal Party committee.

The accident happened at the construction site of Wuhu Huaqiang Culture and Technology Industrial Park at 11:50 a.m., at the end of the workers' morning shift.

Rescuers were still counting the exact number of people being buried, said Zhang.

A rescue operation was underway and police were investigating the cause of the accident.

The park, with a total investment of 2.5 billion yuan (366 million U.S. dollars) from Shenzhen Huaqiang Holdings Limited, is due to open on May 1.