A crane in Hong Kong collapsed at a construction site on Wednesday, leaving three men dead and six others injured. Rescuers spent hours attempting in vain to reach a victim buried under the debris.

Authorities reported that one guy died at the scene in Kowloon after suffering a skull fracture, and another died in the hospital after being taken there.

Urban Search and Rescue Team members from the city worked around a collapsed tower crane that had fallen onto several cargo containers that had been used as temporary offices in an effort to find a third casualty.

"We can only see the lower half of his body, and he was unresponsive when we tried to communicate with him," fire services official Yim Ying-kit said. "(The crane) is quite heavy so we need various tools and risk assessment before we can rescue the trapped worker." Police later confirmed that the man was also deceased.

The crane was in use when it fell shortly before 11 a.m., although it was not hauling any load at the time, according to Yim. He also claimed that some construction employees were in the cargo containers when the crane crashed on them.

Six injured people, including one who was unconscious, were sent to Queen Elizabeth Hospital and United Christian Hospital for medical attention. An investigation, according to the police, is in progress.

Three cranes, including the one that fell, were at the scene, as revealed by online pictures and videos. The downed crane looked to have flattened at least four shipping containers. During the rescue effort, authorities could be seen standing atop some of the containers.

After viewing the site, Secretary of Labour and Welfare Chris Sun told reporters that there was a clear concern with the crane's base and that work at the site had been paused. Hong Kong leader John Lee said the labor department will examine the incident and inspect building sites using cranes to ensure they met safety regulations.

Kwok Wai-keung, a Hong Kong legislator who represents the labor sector, said crane failures are uncommon in the city and that the disaster was a "major blow" to the business. According to police, the crane was installed in August and had been in use prior to Wednesday's disaster.

According to the South China Morning Post, the accident location was a portion of a sizable construction site for a publicly funded housing project with a goal of building 19,000 dwellings.